O, 


AUGUSTA 


w# 


THE 
SEA-BEACH   AT  EBB-TIDE 


THE 


SEA-BEACH  AT  EBB-T 


A  GUIDE  TO  THE  STUDY  OF 
THE  SEAWEEDS  AND  THE 
LOWER  ANIMAL  LIFE  FOUND 
BETWEEN    TIDE-MARKS  14» 


BY 

AUGUSTA   FOOTE   ARNOLD   -^ 

WITH   MORE    THAN 
600   ILLUSTRATIONS 


NEW  YORK 
THE  CENTURY 


And  hath  been  tutor'd  in  the  rudiments 

Of  many  desperate  studies. 

Shakspere. 


Copyright,  1901,  by 
The  Century  Co. 

Piihlished  May,  1901 


A 


The  DeVinne  Press. 


65821 


PREFACE 

THIS  volume  is  designed  to  be  an  aid  to  the  amateur  collector 
and  student  of  the  organisms,  both  animal  and  vegetable, 
which  are  found  upon  North  American  beaches.  In  it  are 
described  many  invertebrates  and  some  of  the  more  notable  varie- 
ties of  seaweeds,  and  each  individual  is  given  its  proper  place  in 
the  latest  classification. 

The  technicality  of  classification  or  scientific  grouping  may 
at  first  seem  repellent,  but  it  in  reality  makes  the  study  of  these 
objects  more  simple ;  and  a  systematic  arrangement  has  been 
adopted  in  the  belief  that  it  is  the  easiest  as  well  as  the  only  sat- 
isfactory way  of  becoming  familiar  with  the  organisms  described. 
Without  it  a  very  confused  picture  of  separate  individuals  would 
be  presented  to  the  mind,  and  a  book  like  the  present  one  would 
become  a  mere  collection  of  isolated  scraps  of  information.  Mor- 
phology, or  the  study  of  structure,  has  been  touched  upon  just 
enough  to  show  the  objects  from  the  biologist's  point  of  view  and 
to  enable  the  observer  to  go  a  little  beyond  the  bare  learning  of 
names. 

Scientific  names  have  been  used  from  necessity,  for  the  plants 
and  animals  of  the  beach  are  so  infrequently  observed,  except  by 
scientific  people,  that  but  few  of  them  have  common  names ; 
and,  as  a  matter  of  fact,  the  reader  will  find  that  a  scientific  name 
is  as  easily  remembered  as  a  common  one.  Technical  phrase- 
ology has,  however,  been  avoided  as  much  as  possible,  even  at  the 


vi  PREFACE 

expense  of  conciseness  and  precision  ;  where  it  has  been  used,  care 
has  been  taken  to  explain  the  terms  so  that  their  meaning  will  be 
plain  to  every  one.  A  general  glossary  has  been  omitted,  but  the 
technical  terms  used  have  been  indexed.  The  illustrations  will 
bear  the  use  of  a  hand-glass,  and  this  will  often  bring  out  details 
which  cannot  well  be  seen  by  the  unaided  eye. 

The  systematic  table  of  the  marine  algae,  as  given  in  Part  I, 
and  followed  in  the  text,  will  be  of  use  to  collectors  who  wish  to 
make  herbaria.  In  order  to  name  and  group  specimens  such  a 
guide  is  necessary.  Should  specific  names  lead  to  embarrassment, 
many  of  them  can  be  neglected,  for  the  names  of  genera  are  often 
a  sufficient  distinction. 

Since  so  many  species  of  invertebrates  are  found  on  the  beach 
that  a  complete  enumeration  of  them  is  impracticable,  only  the 
most  conspicuous  ones  have  been  selected  for  description  in 
Part  II 5  but  the  attempt  has  been  made  to  designate  the  various 
classes  and  orders  with  sufficient  clearness  to  enable  the  collector 
to  identify  the  objects  commonly  found  on  the  shore,  and  to 
follow  the  subject  further,  if  he  so  desires,  in  technical  books. 

It  is  hoped  that  this  book  will  suggest  a  new  interest  and 
pleasure  to  many,  that  it  will  encourage  the  pastime  of  collecting 
and  classifying,  and  that  it  will  serve  as  a  practical  guide  to  a  better 
acquaintance  with  this  branch  of  natural  history,  without  neces- 
sitating serious  study.  Marine  organisms  are  interesting  ac- 
quaintances when  once  introduced,  and  the  real  purpose  of  the 
author  is  to  present,  to  the  latent  naturalist,  friends  whom  he  will 
enjoy. 

Grateful  acknowledgment  is  here  made  to  the  following  per- 
sons who  have  kindly  assisted  and  advised  the  author  and  have 
also  extended  valued  courtesies  to  her  in  the  preparation  of 
this  book :  Smith  Ely  Jelliffe,  M.D.,  Ph.D. ;  Herbert  M.  Richards, 
A.B.,  Ph.D.,  Professor  of  Botany  in  Barnard  College ;  Marshall  A. 


PREFACE  vii 

Howe,  A.B.,  Ph.D.  j  the  Rev.  George  A.  Hoist ;  the  Long  Island 
Historical  Society  of  Brooklyn  for  the  nse  of  its  fine  herbarium, 
containing  the  collections  of  Mr.  John  Hooper,  Mr.  A.  R.  Young, 
and  others,  from  which  most  of  the  illustrations  of  algae  in  this 
book  were  photographed  5  Miss  Toedtleberg,  Librarian  of  the  Long 
Island  Historical  Society ;  Miss  Ingalls,  in  charge  of  the  Museum 
of  the  Long  Island  Historical  Society ;  Dr.  Theodore  Gill  j  James 

A.  Benedict,  Ph.D.,  Assistant  Curator  of  Marine  Invertebrates 
in  the  Smithsonian  Institution ;  Miss  Mary  J.  Rathbun,  second 
Assistant  Curator  of  Marine  Invertebrates  in  the  Smithsonian 
Institution ;  Miss  Harriet  Richardson  ;  and  especially  to  Mr.  John 

B.  Henderson,  Jr. 

Thanks,  also,  are  due  to  Messrs.  Macmillan  &  Co.  for  permis- 
sion to  use  cuts  from  the  "  Cambridge  Natural  History,"  Parker 
and  Haswell's  "Zoology,"  and  Murray's  ''Introduction  to  the 
Study  of  Seaweeds" ;  to  Swan  Sonnenschein  &  Co.  for  the  use  of  cuts 
from  Sedgwick's  "Student's  Text-book  of  Zoology";  to  Wilhelm 
Engelmann  for  a  cut  from  "Die  natiirlichen  Pflanzenf amilien " 
of  Engler  and  Prantl ;  to  Little,  Brown  &  Co.  for  permission  to 
reproduce  illustrations  from  Agassiz's  "  Contributions  to  the 
Natural  History  of  the  United  States  "  ;  to  Henry  Holt  &  Co.  for  a 
cut  from  McMurrich's  "  Invertebrate  Morphology  " ;  to  Houghton, 
Miflin  &  Co.  for  cuts  from  the  "  Riverside  Natural  History " 
and  Agassiz's  "  Seaside  Studies  in  Natural  Histor}^ " ;  to  the  Com- 
monwealth of  Massachusetts  for  the  use  of  illustrations  from 
Verrill's  "  Report  upon  the  Invertebrate  Animals  of  Vineyard 
Sound  and  the  Adjacent  Waters,"  Gould's  "  Invertebrata  of 
Massachusetts"  (ed.  Binney),  and  certain  fisheries  reports;  and 
to  the  United  States  government  for  illustrations  taken  from 
Bulletin  37  of  the  Smithsonian  Institution  and  from  reports  of  the 
United  States  Fish  Commission. 


CONTENTS 

Introduction 

PAGE 

I  Signs  on  the  Beach 1 

II  Collecting 6 

III  Classification 19 

IV  Animal  Life  in  its  Lowest  Forms 21 

V  Distribution  of  Animal  Life  in  the  Sea 23 

VI  Some  Botanical  Facts  about  Algae 25 

VII  Naming  of  Plants 28 

VIII  Distribution  of  Algae 30 

IX  Some  Peculiar  and  Interesting  Varieties  of  Algae 32 

X  Uses  of  Algae 37 

XI  Collecting  at  Bar  Harbor 40 

*^  PAET   I 

Marine  Alg^ 

I  Blue-Green  Seaweeds 47 

(Cyanophyce^) 

Grass-Green  Seaweeds 47 

(Chlorophyce^) 

II  Olive-Green  and  Brown  Seaweeds 61 

(Ph^ophyce^) 

III  Red  Seaweeds - 75 

(Rhodophyce^  or  Floride^) 

PART   II 

Marine  Invertebrates 

I  Porifera  (Sponges) 99 

II  Ccelenterata  (Polyps' Ill 

ix 


CONTENTS 
Marine  Invertebrates  {Continued) 

PAGE 

III  Worms 159 

(Platyhelminthes,  Nemathelminthes,  Annulata) 

iv  molluscoida 187 

V  Echinodermata 199 

VI  Arthropoda 237 

VII  MOLLUSCA 299 

VIII  Chordata 471 

Index 479 


INTRODUCTION 


In  vain  through  every  changeful  year 

Did  nature  lead  him  as  before  ; 
A  primrose  by  a  river's  brim, 
A  yellow  primrose  was  to  him, 

And  it  was  nothing  more. 

At  noon,  when  by  the  forest's  edge 
He  lay  beneath  the  branches  high, 
The  soft  blue  sky  did  never  melt 
Into  his  heart ;  he  never  felt 
The  witchery  of  the  soft  blue  sky. 

Wordsworth. 

To  him  who  in  the  love  of  Nature  holds 
Communion  with  her  visible  forms,  she  speaks 
A  various  language. 

Bryant. 


Xll 


INTRODUCTION 


SIGINS  ON  THE   BEACH 

THE  sea-shore,  with  its  stretches  of  sandy  beach  and  rocks, 
seems,  at  first  sight,  nothing  bnt  a  barren  and  uninteresting 
waste,  merely  the  natural  barrier  of  the  ocean.  But  to  the  obser- 
vant eye  these  apparently  desolate  reaches  are  not  only  teeming 
with  life;  they  are  also  replete  with  suggestions  of  the  past. 
They  are  the  pages  of  a  history  full  of  fascination  for  one  who 
has  learned  to  read  it. 

In  this  history  even  the  grains  of  sand  have  a  part.  Though 
so  humble  now,  they  once  formed  the  rocky  barriers  of  the  shore. 
They  stood  as  do  the  rocks  of  to-day,  defiant  and  seemingly  ever- 
lasting, but  the  fui'y  of  the  sea,  which  knows  no  invincible  adver- 
sary, has  laid  them  low.  Every  coast-line  shows  the  destructive 
effects  of  the  sea,  for  the  bays  and  coves,  the  caves  at  the  bases 
of  the  cliffs,  the  buttresses,  stocks,  needles,  and  skerries,  are  the 
work  of  the  waves.     And  this  work  is  constantly  going  on. 

Even  a  blind  man  could  not  stand  long  upon  a  shingly  beach 
without  knowing  that  the  sea  was  busily  at  work.  Every 
wave  that  rolls  in  from  the  open  ocean  hurls  the  pebbles  up 
the  slope  of  the  beach,  and  then  as  soon  as  the  wave  has  broken 
and  the  water  has  dispersed,  these  pebbles  come  rattling  down 
with  the  currents  that  sweep  back  to  the  sea.  The  clatter  of 
the  beach  thus  tells  us  plainly  that  as  the  stones  are  being 
dragged  up  and  down  they  are  constantly  knocked  against 
each  other;  and  it  is  evident  that  by  such  rough  usage  all 
1  1 


2  INTRODUCTION 

angular  fragments  of  rock  will  soon  have  their  corners 
rounded  off  and  become  rubbed  into  the  form  of  pebbles.  As 
these  pebbles  are  rolled  to  and  fro  upon  the  beach  they  get 
worn  smaller  and  smaller,  until  at  length  they  are  reduced  to 
the  state  of  sand.  Although  this  sand  is  at  first  coarse,  it 
gradually  becomes  finer  and  finer  as  surely  as  though  it  were 
ground  in  a  mill ;  and  ultimately  it  is  carried  out  to  sea  as 
fine  sediment  and  laid  down  upon  the  ocean  floor. ^ 

The  story  of  the  sands  is  not  only  one  of  the  conflict  of  the  sea 
and  rocks  j  it  is  also  a  story  of  the  winds.  It  is  the  winds  that 
have  rescued  them  from  the  waves  and  driven  them  about,  sifting 
and  assorting  them,  arranging  them  in  graceful  forms,  and  often 
heaping  them  up  into  dunes  which,  until  fastened  by  vegetation, 
are  themselves  ever  moved  onward  by  the  same  force,  sometimes 
burying  fertile  lands,  trees,  and  even  houses  in  their  march. 
The  sands,  moreover,  are  in  turn  themselves  destructive  agents, 
to  whose  power  the  many  fragments  which  strew  the  beach  and 
dunes  bear  ample  witness.  The  knotty  sticks  so  commonly  seen 
on  the  beach  are  often  the  hearts  of  oak-  or  cedar-trees  from 
which  the  tiny  crystals  of  sand  have  slowly  cut  away  their  less 
solid  outer  growth.  Everything,  in  fact,  upon  the  sands  is 
"beach-worn,"  even  to  the  window- glass  of  life-saving  stations, 
which  is  frequently  so  ground  that  it  loses  its  transparency  in  a 
single  storm. 

The  beach  is  also  a  vast  sarcophagus  holding  myriads  of  the 
dead.  "  If  ghosts  be  ever  laid,  here  lie  ghosts  of  creatures  innu- 
merable, vexing  the  mind  in  the  attempt  to  conceive  them." 
And  there  are  certain  sands  which  may  be  said  to  sing  their 
requiem,  the  so-called  musical  sands,  like  the  "Singing  Beach" 
at  Manchester-by-the-Sea,  which  emit  sounds  when  struck  or  other- 
wise disturbed.  On  some  beaches  these  sounds  resemble  rumbling, 
on  others  hooting ;  sometimes  they  are  bell-like  and  even  rhyth- 
mical. The  cause  of  this  sonorous  character  is  not  definitely 
known,  but  it  is  possibly  due  to  films  of  compressed  gases  which 
separate  each  grain  as  with  a  cushion,  and  the  breaking  of  which 

1  Huxley. 


SIGNS  ON  THE  BEACH  3 

causes,  in  the  aggregate,  considerable  vibrations.  Sucb.  sands 
are  not  nncommon,  having  been  recorded  in  many  places,  and 
they  exist  probably  in  many  others  where  they  have  escaped 
observation.  They  may  be  looked  for  above  the  water-line, 
where  the  sand  is  dry  and  clean. 

We  have  to  do,  however,  in  this  volume,  not  with  the  history 
of  the  past,  nor  with  the  action  of  physical  forces,  but  with  the 
life  of  the  present,  and  to  find  this,  in  its  abundance,  one  must 
go  down  near  the  margin  of  the  water,  where  the  sands  are  wet. 
There  is  no  solitude  here ;  the  place  is  teeming  with  living  things. 
As  each  wave  retreats,  little  bubbles  of  air  are  plentiful  in  its 
wake.  Underneath  the  sand,  where  each  bubble  rose,  lives  some 
creature,  usually  a  mollusk,  perhaps  the  razor-shell  Solen  ensis. 
By  the  jet  of  water  which  spurts  out  of  the  sand,  the  common 
clam  Mya  arenaria  reveals  the  secret  of  its  abiding-place.  A 
curious  groove  or  furrow  here  and  there  leads  to  a  spot  where 
Folynices  heros  has  gone  below;  and  the  many  shells  scattered 
about,  pierced  with  circular  holes,  tell  how  Polynices  and  Nassa 
made  their  breakfast  and  their  dinner.  Only  the  lifting  of  a 
shovelful  of  sand  at  the  water's  edge  is  needed  to  disclose  the 
populous  community  of  mollusks,  worms,  and  crustaceans  living 
at  our  feet.  Just  out  of  sight. 

Even  the  tracks  and  traces  of  these  little  beings  are  full  of 
information.  What  may  be  read  in  the  track  of  a  bird  on  the 
sand  is  thus  described  by  a  noted  ornithologist : 

Here  are  foot-notes  again,  this  time  of  real  steps  from  real 
feet.  .  .  .  The  imprints  are  in  two  parallel  lines,  an  inch  or 
so  apart;  each  impression  is  two  or  three  inches  in  advance 
of  the  next  one  behind ;  none  of  them  are  in  pairs,  but  each 
one  of  one  line  is  opposite  the  middle  of  the  interval  between 
two  of  the  other  line ;  they  are  steps  as  regular  as  a  man's, 
only  so  small.  Each  mark  is  fan-shaped  ;  it  consists  of  three 
little  lines  less  than  an  inch  long,  spreading  apart  at  one  ex- 
tremity, joined  at  the  other.  At  the  joined  end,  and  also  just 
in  front  of  it,  a  flat  depression  of  the  sand  is  barely  visible. 
Now  following  the  track,  we  see  it  run  straight  a  yard  or 


4  INTRODUCTION 

more,  then  twist  into  a  confused  ball,  then  shoot  out  straight 
again,  then  stop,  with  a  pair  of  the  footprints  opposite  each 
other,  different  from  the  other  end  of  the  track,  that  began 
as  two  or  three  little  indistinct  pits  or  scratches,  not  forming 
perfect  impressions  of  a  foot.  Where  the  track  twisted  there 
are  several  little  round  holes  in  the  sand.  The  whole  track 
commenced  and  finished  upon  the  open  sand.  The  creature 
that  made  it  could  not,  then,  have  come  out  of  either  the 
sand  or  the  water;  it  must  have  come  down  from  the  air— a 
two-legged  flying  thing,  a  bird.  To  determine  this,  and,  next, 
what  kind  of  bird  it  was,  every  one  of  the  trivial  points  of  the 
description  just  given  must  be  taken  into  account.  It  is  a 
bit  of  autobiography,  the  story  of  an  invitation  to  dine,  ac- 
ceptance, a  repast,  an  alarm  at  the  table,  a  hasty  retreat.  A 
bird  came  on  wing,  lowering  till  the  tips  of  its  toes  just 
touched  the  sand,  gliding  half  on  wing,  half  afoot,  until  the 
impetus  of  flight  was  exhausted;  then  folding  its  wings,  but 
not  pausing,  for  already  a  quick  eye  spied  something  inviting ; 
a  hasty  pecking  and  probing  to  this  side  and  that,  where  we 
found  the  lines  entangled ;  a  short  run  after  more  food ;  then 
a  suspicious  object  attracted  its  attention ;  it  stood  stock-stiU 
(just  where  the  marks  were  in  a  pair),  till,  thoroughly 
alarmed,  it  sprang  on  wing  and  was  off.^ 

Following  the  key  further,  he  draws  more  conclusions.  The 
tracks  are  not  in  pairs,  so  the  bird  does  not  belong  to  the  perch- 
ers;  therefore  it  must  be  a  wader  or  a  swimmer.  There  are  no 
web-marks  to  indicate  the  latter ;  hence  it  is  a  three-toed  walk- 
ing or  wading  bird.  It  had  flat,  long,  narrow,  and  pointed  wings 
because  it  came  gliding  swiftly  and  low,  and  scraped  the  sand 
before  its  wings  were  closed.  This  is  shown  by  the  few  scratches 
before,  the  prints  became  perfect.  A  certain  class  of  birds  thus 
arrests  the  impetus  of  flight.  It  had  a  long  feeling-bill,  as  shown 
by  the  little  holes  in  the  sands  where  the  marks  became  entan- 
gled ;  and  so  on.  These  combined  characteristics  belong  to  one 
class  of  birds  and  to  no   other;  so  he  knows  as  definitely  as 

1  Elliott  Cones. 


SIGNS  ON  THE  BEACH  5 

thougli  he  had  seen  the  bird  that  a  sandpiper  alighted  here  for  a 
brief  period,  for  here  is  his  signature. 

It  is  plain  that  tracks  in  the  sand  mean  as  much  to  the  natu- 
ralist as  do  tracks  in  the  snow  to  the  hunter,  and  trails  on  the 
land  to  the  Indian  who  follows  his  course  by  signs  not  seen  by 
an  untrained  eye. 

The  tide  effaces  much  that  is  written  by  foot  and  wing,  but 
sometimes  such  signs  are  preserved  and  become  veritable  "foot- 
prints on  the  sands  of  time."  In  the  Museum  of  Natural  History 
in  New  York  is  a  fossil  slab,  taken  from  the  Triassic  sandstone, 
showing  the  footprints  of  a  dinosaurian  reptile  now  extinct, 
which,  in  that  long  ago,  walked  across  a  beach— an  event  unim- 
portant enough  in  itself,  but  more  marvelous  than  any  tale  of 
imagination  when  recorded  for  future  ages.  From  such  tracks, 
together  with  fragments  of  skeletons,  the  dinosaur  has  been 
made  to  live  again,  and  its  form  and  structure  have  been  as 
clearly  defined  as  those  of  the  little  sandpiper  of  Dr.  Coues. 


II 

COLLECTINGl 

IT  has  been  said  that  everything  on  the  land  has  its  counterpart 
in  the  sea.  But  all  land  animals  are  separate  and  indepen- 
dent individuals,  while  many  of  those  of  the  sea  are  united  into 
organic  associations  comprising  millions  of  individuals  insepara- 
bly connected  and  many  of  them  interdependent,  such  as  corals, 
hydroids,  etc.  These  curious  communities  can  be  compared  only 
to  the  vegetation  of  the  land,  which  many  of  them  resemble  in 
outer  form.  Other  stationary  animals,  such  as  oysters  and 
barnacles,  which  also  depend  upon  floating  organisms  for  their 
food,  have  no  parallel  on  the  land. 

The  water  is  crowded  with  creatures  which  prey  upon  one 
another,  and  all  are  interestingly  adapted  to  their  mode  of  life. 
Shore  species  are  exceedingly  abundant,  and  the  struggle  for  life 
is  there  carried  on  with  unceasing  strife.  In  the  endeavor  to 
escape  pursuers  while  they  themselves  pursue,  these  animals 
have  various  devices  of  armature  and  weapons  of  defense ;  they 
have  keen  vision,  rapid  motion,  and  are  full  of  arts  and  wiles. 
One  of  the  first  resources  for  safety  in  this  conflict  is  that  of  con- 
cealment. This  is  effected  not  only  by  actual  hiding,  but  very 
generally  by  mimicry  in  simulating  the  color  of  their  surround- 
ings, and  often  by  assuming  other  forms.  Thus,  for  instance, 
the  sea-anemone  when  expanded  looks  like  a  flower  and  is  full  of 
color,  but  when  it  contracts  becomes  so  inconspicuous  as  to  be 
with  difiiculty  distinguished  from  the  rock  to  which  it  is  attached. 
They  also  have  stinging  threads  (nematophores),  which  they  dart 

out  for  further  defense. 

6 


COLLECTING  7 

The  study  of  biology  has  great  fascination,  and  the  subject 
seldom  fails  to  awaken  interest  as  soon  as  the  habit  of  observa- 
tion is  formed.  Jellyfishes,  hardly  more  dense  than  the  water 
and  almost  as  limpid,  swimming  about  with  graceful  motion, 
often  illuminating  the  water  at  night  with  their  phosphorescence, 
showing  sensitiveness,  volition,  and  order  in  their  lives,  cannot 
fail  to  excite  wonder  in  even  the  most  careless  observer.  Not 
less  interesting  are  the  thousands  of  other  animals  which  crowd 
the  shores,  lying  just  beneath  the  surface  of  the  sand,  filling 
crevices  in  the  rocks,  hiding  under  every  projection,  or  boldly — 
perhaps  timidly,  who  shall  say  ?— lying  in  full  view,  yet  so  incpn- 
spicuous  that  they  are  easily  passed  by  unnoticed. 

To  find  these  creatures,  to  study  their  habits  and  organization, 
to  consider  the  wonderful  order  of  nature,  leads  through  dehght- 
ful  paths  into  the  realms  of  science.  But  even  without  scientific 
study  the  simple  observation  of  the  curious  objects  which  lie  at 
one's  feet  as  one  walks  along  the  beach  is  a  delightful  pastime. 

The  features  which  separate  the  classes  and  the  orders  of  both 
the  plant  and  the  animal  life  are  so  distinctive  that  it  requires 
but  very  superficial  observation  to  know  them.  It  is  easy  to 
discriminate  between  moUusks,  echinoderms,  and  polyps,  and  to 
recognize  the  relationship  between  univalves  and  bivalves,  sea- 
urchins  and  starfishes,  sea-anemones  and  corals.  The  equally 
plain  distinctions  between  the  branched,  unbranched,  tubular, 
and  plate-like  green  alga3  make  them  as  easy  to  separate. 

The  pleasure  of  a  walk  through  field  or  forest  is  enhanced  by 
knowing  something  of  the  trees  and  flowers,  and  in  the  same  way 
a  visit  to  the  sea-shore  becomes  doubly  interesting  when  one  has 
some  knowledge,  even  though  it  be  a  very  superficial  one,  of  the 
organisms  which  inhabit  the  shore. 

ROCKY   SHORES 

Rocky  shores  furnish  an  abundance  and  great  variety  of  objects 
to  the  collector.  The  seaweeds  here  find  places  of  attachment, 
and  the  lee  and  crevices  of  the  rocks  afford  shelter  to  many  ani- 
mals which  could  not  live  in  more  open  and  exposed  places.     The 


8  INTRODUCTION 

rock  pools  harbor  species  whose  habitat  is  below  low-water  mark 
and  which  could  not  otherwise  bear  the  alternation  of  the  tides. 

The  first  objects  on  the  rocky  beach  to  attract  attention  are 
the  barnacles  and  rockweeds.  They  are  conspicuous  in  their  pro- 
fusion, the  former  incrusting  the  rocks  with  their  white  shells, 
and  the  latter  forming  large  beds  of  vegetation ;  yet  both  are 
likely  to  be  passed  by  with  indifference  because  of  their  plentiful 
ness.  They  are,  however,  not  only  interesting  in  themselves, 
but  associated  with  them  are  many  organisms  which  are  easily 
overlooked.  The  littoral  zone  is  so  crowded  with  life  that  there 
is  a  constant  struggle  for  existence,— even  for  standing-room,  it 
may  be  said,— and  no  class  of  animals  has  undisputed  possession 
of  any  place.  Therefore  the  collector  should  carefully  search 
any  object  he  gathers  for  other  organisms  which  may  be  upon  it, 
under  it,  or  even  in  it,  such  as  parasites,  commensals,  and  the 
organisms  which  hide  under  it  or  attach  themselves  to  it  for  sup- 
port. Let  the  rockweed  {Fucus)  be  carefully  examined.  Among 
the  things  likely  to  be  found  attached  to  its  fronds  are  periwinkles 
{Littorina  litorea),  which  simulate  the  plant  in  color,  some  shells 
being  striped  for  closer  mimicry.  Sertularian  hydroids  also  are 
there,  zigzagging  over  the  fronds  or  forming  tufts  of  delicate 
horny  branches  upon  them.  Small  jelly-like  masses  at  the  broad 
divisions  of  the  fronds  may  be  compound  ascidians.  Calcareous 
spots  here  and  there  may  be  polyzoans  of  exquisite  form,  while 
spread  in  incrusting  sheets  over  considerable  spaces  are  other 
species  of  Polyzoa.  Tiny  flat  shelly  spirals  are  the  worm-cases  of 
SpirorUs.  A  pocket-lens  is  essential  to  enable  one  to  appreciate 
the  beauty  of  these  minute  forms.  Under  the  rockweeds  are 
many  kinds  of  crustaceans ;  perhaps  there  will  also  be  patches  of 
the  pink  urn-like  egg-capsules  of  Purpura  at  the  base  of  the  fucus. 

Various  kinds  of  seaweed  abound  in  the  more  sheltered  parts 
of  the  rocks,  and  among  them  will  be  found  amphipods  and  iso- 
pods,  many  of  which  are  of  species  different  from  those  of  the 
sandy  beaches.  Here,  too,  is  the  little  Caprella,  imitating  the 
seaweed  in  form,  and  swaying  its  lengthened  body,  which  is 
attached  to  the  plant  only  by  its  hind  legs.  On  the  seaweeds,  as 
weU  as  in  the  tide-pool,  may  be  found  beautiful  hydroids,  and  on 


COLLECTING  9 

tliem  the  curious  little  sea-spiders  {Pycnogonidce),  animals  which 
seem  to  be  all  legs. 

Mollusks,  and  other  classes  as  well,  differ  in  different  latitudes. 
On  the  rocks  of  the  Northern  shores  lAttorina  and  Purpura  shells 
are  very  abundant,  the  latter  in  various  colors  and  beautifully 
striped.  Limpets  are  also  plentiful,  but  are  not  as  conspicuous, 
since  they  have  flat,  disk-shaped  shells.  When  their  capture  is 
attempted,  they  must  be  taken  unawares  and  pushed  quickly 
aside,  else  they  take  such  a  firm  hold  of  the  rock  that  it  is  diffi- 
cult to  dislodge  them.  Near  low-water  mark  under  ledges  will 
perhaps  be  found  chitons,  which  are  easily  recognized  by  their 
oval,  jointed  shells.  On  the  California  coast  in  like  localities 
will  be  found  the  beautiful  Raliotis,  AcmcBci,  and  chitons.  Every 
stone  that  is  lifted  will  disclose  numbers  of  little  amphipods 
(Gammarus),  which  will  scuttle  away  on  their  sides  to  other 
shelter;  worms  will  suddenly  disappear  into  the  mud,  and  per- 
haps a  crab,  here  and  there,  having  no  alternative,  will  make  a 
stand  and  fight  for  his  liberty.  Flat  against  the  stone  and  not 
easily  perceived  may  be  a  chiton,  a  planarian  worm,  or  a  nudi- 
branch.  And  just  below  the  water's  edge  are  sea-urchins  and 
starfishes,  which  grow  in  numbers  as  the  eye  becomes  accustomed 
to  the  search. 

The  rock  pools  are  natural  aquaria,  more  interesting  by  far 
than  any  prepared  by  man.  The  possibilities  of  these  little  sea- 
gardens  are  beyond  enumeration.  The  longer  one  studies  them 
the  more  one  finds.  In  them  all  classes  of  seaweeds  and  marine 
invertebrates  may  be  found  and  their  habits  watched.  The  great 
beauty  of  these  pools  gives  them  an  esthetic  charm  apart  from 
the  scientific  interest  they  excite.  Perhaps  one  may  find  here  a 
sponge,  and  removing  it  to  a  shallow  vessel  of  sea-water  can 
watch  the  currents  of  water  it  creates.  Several  sponges  of  the 
same  species  placed  in  contact  will  at  the  end  of  two  days  be 
closely  united.  If  the  sponges  are  of  different  species  they  will 
not  coalesce. 

In  the  clefts  and  crannies  of  the  rocks  are  various  fine  sea- 
weeds, often  of  the  red  varieties,  sea-anemoneS,  hydroids,  poly- 
zoans,  crustaceans,  mollusks,  and  ascidians.     Crabs  will  be  snugly 


10  INTRODUCTION 

ensconced  under  projecting  surfaces.  Most  species  are  more 
plentiful  at  the  lowest-water  mark,  and  many  are  foimd  only  at 
this  point  and  below. 

SANDY  SHORES 

On  sandy  shores  the  greater  part  of  the  inhabitants  live  under 
the  surface.  Many  give  evidence  of  their  presence  by  the  open 
mouths  of  their  burrows,  and  some  distinctly  point  out  these 
places  by  piles  of  sand  or  mud  in  coils  at  the  opening.  Some 
tubicolous  worms  have  their  tubes  projecting  above  the  surface. 
The  tubes  of  Biopatra  are  hung  with  bits  of  shells,  seaweeds,  and 
other  foreign  matter.  Some  mollusks  announce  themselves  by 
spurting  jets  of  water  or  sending  bubbles  of  air  from  the  sand. 
The  majority  of  the  underground  species,  however,  give  no  sign 
of  their  presence  on  the  surface,  and  must  be  found  by  digging. 
Many  of  them  go  deep  into  the  sand,  and  in  searching  for  worms 
the  digger  must  be  quick  and  expert,  or  he  will  lose  entirely  or 
cut  in  two  many  of  the  most  beautiful  ones,  which  retreat  quickly 
and  to  the  extremity  of  their  holes  at  the  least  alarm.  One  can 
be  a  rambler  on  the  sandy  beach  for  a  long  time  without  being 
aware  of  the  many  beautiful  objects  which  inhabit  the  subsurface 
of  the  sand.  The  curious  crab  Hippa  will  disappear  so  quickly 
into  the  sand  that  one  is  hardly  sure  he  has  really  seen  it.  The 
vast  number  of  worms  will  surprise  any  one  who  searches  for 
them  by  their  variety,  their  beautiful  color,  and  their  interesting 
shapes.  Here  again  a  glass  is  requisite  to  appreciate  the  delicacy 
and  beauty  of  their  locomotive  organs,  their  branchise,  and  so  on. 
The  most  common  of  the  gasteropod  mollusks  on  sandy  shores 
are  Nassa  ohsoleta,  N'assa  trivittata,  and  Polynices  (Lunatia)  lieros. 
The  last  are  detected  by  the  little  mounds  of  sand  which  they 
push  before  them  as  they  plow  their  way  just  below  the  surface. 
On  more  southern  beaches,  Fulgur,  Stromhis,  and  Pyemia  are  the 
common  varieties.  OUvella,  OUva,  and  Donax,  also  inhabitants  of 
sandy  beaches,  will  quickly  disappear  when  uncovered  by  the 
waves,  being  rapid  burrowers.  Most  of  the  many  dead  shells  on 
the  beach  will  be  found  to  be  pierced  with  a  round  hole,  which  is 


PLATE 

Egg-capsules  of  Purpura  lapillus. 
Egg-capsules  of  Buccinuin  undatum. 
Fulgur  canaliculata  (whelk)  and  egg-cases. 


Egg-case  of  Polynices  heros. 
Egg-case  of  the  skate. 


COLLECTING  11 

drilled  by  the  file-like  tongue,  or  lingual  ribbon,  of  Folynices, 
Urosalpinx,  or  JSfassa,  which  thus  reach  the  animal  within  and 
suck  out  its  substance.  Another  similar  species  is  Folynices 
{Neverita)  dupUcata,  which  extends  to  the  Gulf  of  Mexico,  while 
P.  heros  is  not  commonly  found  below  Hatteras.  Crustaceans 
are  abundant  on  the  sandy  beach  over  its  whole  breadth.  Some 
of  the  sand-crabs  live  above  tide-mark.  Among  these  is  the 
fleet-footed  Ocypoda,  which  is  interesting  to  watch.  Often  they 
go  in  numbers  to  the  water's  edge  and  throw  up  mounds,  behind 
which  they  crouch  like  cats,  watching  for  whatever  prey  the  tide 
may  bring  up.  When  unable  to  outrun  a  pursuer  they  rush  into 
the  surf  and  remain  there  until  the  danger  is  past.  The  wet 
sand  is  often  thickly  perforated  with  the  burrows  of  the  sand- 
hoppers  {OrcJiestia).  These  often  rise  about  the  feet  as  do  grass- 
hoppers in  the  fields. 

Hippa  talpoida  is  a  remarkable  crab,  somewhat  resembling  an 
egg.  It  is  not  likely  to  be  seen  unless  searched  for  by  digging 
at  the  water's  edge.  It  burrows  so  rapidly  that  one  must  be 
quick  to  catch  it  after  it  is  exposed  by  the  shovel.  In  some 
places  the  tests  of  '^  sand-dollars "  are  common.  The  living 
animal  may  be  found  buried  just  below  the  surface  at  extreme 
low- water  mark. 

The  sea- wrack  drifted  in  lines  along  the  shore  will  repay  care- 
ful examination,  for  here  will  be  found  many  things  belonging 
to  other  shores  and  deep  water.  It  is  often  alive  with  sand- 
hoppers,  which  hop  away  while  one  searches  for  less  common 
things.  Often  the  most  delicate  seaweeds,  numerous  small  shells, 
worms,  polyzoans,  etc.,  will  be  found  there. 

The  surface  of  the  sand-beach  is  strewn  with  remains  of  many 
species,  usually  beach- worn,  but  interesting  nevertheless  as  ex- 
amples of  species  one  would  like  to  find  in  better  condition,  but 
good  specimens  of  which  elude  ordinary  search  or  are  unobtain- 
able except  by  dredging. 

Egg-cases  form  another  class  of  objects  which  are  often 
gathered  with  no  idea  of  their  identity.  Of  these  the  most  com- 
mon are  the  long  strings  of  saucer-like  capsules  which  contain 
the  eggs  of  the  mollusk  Fulgur,  those  having  square  edges  being 


12  INTRODUCTION 

the  egg-cases  of  F.  carica,  and  those  having  sharp  edges  those  of 
F.  canaliculata.  Collar-like  sandy  rings  contain  the  eggs  of 
Polynices  (Lunatia),  which  are  cemented  together  in  this  shape. 
The  boys  of  Cape  Cod  call  them  "tommy-cod  honses."  Cylindri- 
cal piles  of  little  capsules,  sometimes  called  "  ears  of  corn,"  hold 
the  eggs  of  Chrysodomus.  The  irregular  masses  of  small  hemi- 
spherical capsules  are  those  of  the  common  whelk  (Buccimim). 
The  so-called  "Devil's  pocket-books"  are  the  egg-cases  of  the  skate. 

MUDDY  SHORES 

On  muddy  shores  the  eel-grass  {Zostera  marina)  grows  abun- 
dantly, giving  an  appearance  of  submerged  meadows.  It  is  one 
of  the  very  few  flowering  plants  which  live  in  salt  water.  In 
summer  its  little  green  blossoms  may  be  seen  in  grooves  on  the 
leaf-like  blades.  Many  animals  live  on  and  among  eel-grass. 
Found  upon  it  is  the  delicate  gasteropod  moUusk  Lacuna  vincta, 
and  its  eggs  in  little  rings ;  the  iridescent  Margarita  heUcina,  and 
Nassa,  with  its  bright-yellow  eggs  in  small  gelatinous  masses ; 
also  little  worms  {Spirorhis)  in  tiny  flat  spiral  shells,  compound 
ascidians  in  jelly-like  masses,  clusters  of  shelly  or  horny  poly- 
zoans,  isopods,  planarian  worms,  and  so  on.  Scallops  (Pecten) 
will  be  found  at  the  base  of  the  plants,  and  the  common  prawns 
are  very  numerous,  swimming  freely  about.  Mud  flats  and 
shores  are  the  homes  of  many  moUusks,  especially  of  N^assa  obso- 
leta, — which  is  the  most  abundant  shell  of  any  considerable  size 
from  Cape  Cod  to  the  Gulf  of  Mexico, — and  of  vast  numbers  of  the 
tiny  Littorinella  minuta,  which  serve  as  food  for  fishes  and  aquatic 
birds.     Clams  and  worms  of  all  varieties  are  also  abundant. 

There  are  many  varieties  of  mud-crabs,  of  which  the  most  com- 
mon are  the  "  fiddlers,"  which  honeycomb  the  banks  and  the  sur- 
face of  salt-marshes  with  their  burrows.  The  common  edible 
crab  CaUinedes  liastatus  is  plentiful  in  bays  and  estuaries.  The 
sluggish  spider-crabs  hide  beneath  the  surface  of  the  mud  and  in 
decaying  weeds  and  eel-grass.  Hermit-crabs  are  plentiful  here 
as  well  as  elsewhere.  Panopeus  is  a  sluggish  crab  found  in  shal- 
low water  and  in  all  sorts  of  hiding-places  along  the  shore.      It 


COLLECTING  13 

may  often  be  found  in  dead  shells,  and,  in  the  South,  in  holes  in 
the  banks.  This  genus  is  represented  by  a  number  of  species, 
some  of  which  are  quite  pretty. 

WHARVES   AND    BRIDGES 

On  the  piles  of  wharves  and  bridges  may  often  be  found  beau- 
tiful tubularian  hydroids  in  large  tufts  just  below  low-water 
mark,  branched  hydroids  looking  like  little  shrubs,  polyzoans, 
sea-anemones,  moUusks,  and  ascidians.  The  species  peculiar  to 
these  localities  are  the  boring  mollusk  Teredo  navalis,  or  ship- 
worm,  the  boring  isopod  Idmnoria  lignortmi,  and  the  boring 
amphipod  Chehira  terebrans,  all  of  which  penetrate  the  wood  and 
are  most  destructive. 

The  animals  and  plants  of  tropical  beaches  and  coral  reefs  are 
so  various  and  abundant,  so  curious  and  beautiful,  as  to  make  a 
description  or  even  an  enumeration  of  them  in  a  brief  space  diffi- 
cult. The  collector  is  bewildered  and  excited  when  he  first  views 
the  profusion  of  the  wonderful  forms  there  found. 

It  is  not  generally  known  that  a  fine  species  of  ^'  stony  coral " 
is  common  from  Cape  Cod  southward,  growing  in  clear  water  as 
an  incrustation  on  rocks,  and  developing  little  spires  as  it 
advances  in  age.  This  species,  the  Astrangia  danae,  is  especially 
interesting,  since  it  will  live  in  a  dish  of  clear  sea- water,  and  the 
polyps  will  expand,  showing  a  very  close  relationship  to  the  sea- 
anemone.  With  care  in  changing  the  water  this  coral  will  live 
for  days,  and  may  be  examined  in  its  expanded  condition  with  a 
lens  of  moderate  power. 

The  most  favorable  time  for  collecting  on  any  beach  is  at  the 
lowest  tide,  many  objects  being  then  uncovered  which  do  not 
appear  higher  up  on  the  beach.  At  the  spring-tides,  which  occur 
twice  a  month,  at  the  period  of  the  new  and  that  of  the  full 
moon,  the  ebb  is  especially  low,  and  affords  an  opportunity  to 
search  for  forms  whose  habitat  is  below  ordinary  low-water 
mark.  During  storms  deep-water  forms  are  often  torn  from  their 
beds  and  cast  upon  the  beach.  Shore-collecting  at  these  times  is 
often  very  interesting. 


14  INTRODUCTION 

EQUIPMENT  FOR  COLLECTING  INVERTEBRATES 

The  equipment  for  coUectiug  upon  sandy  beaches  is  a  shovel, 
a  sieve,  and  a  net.  Numerous  trials  should  be  made  with  the 
shovel  from  about  half -tide  mark  to  as  deep  as  one  cares  to  wade, 
and  the  sand  raised  should  be  carefully  searched  for  shells,  crus- 
taceans, and  worms.  By  washing  out  the  sand  in  the  sieve  the 
smallest  specimens,  which  might  otherwise  escape  notice,  may  be 
secured.  On  a  rocky  beach  a  strong  knife  and  a  net  are  suffi- 
cient. It  is  well  to  have  a  number  of  homeopathic  vials  for  small 
specimens,  which  will  be  injured  by  contact  with  larger  forms, 
and  jars  for  holding  the  general  collection. 

PRESERVING  INVERTEBRATES 

To  preserve  specimens,  they  should  first  be  placed  in  a  weak 
solution  of  alcohol,  the  strength  of  which  should  be  increased 
gradually  until  the  animal  is  entirely  free  from  water  and  is 
hardened  throughout.  If  the  alcohol  becomes  colored  and  sedi- 
ment falls  to  the  bottom  of  the  jar,  the  animal  is  degenerating, 
and  the  alcohol  should  be  changed.  Specimens  for  transporta- 
tion can  be  packed  by  wrapping  each  one  in  a  bit  of  cheese-cloth 
and  then  placing  them  together  in  a  large  receptacle.  Care 
should  be  taken  to  keep  the  fragile  specimens  separate.  Sand- 
dollars  possess  a  pigment  which  discolors  and  soon  vitiates  alcohol, 
and  consequently  these  should  be  separated  from  the  other  forms 
and  placed  where  the  alcohol  may  be  changed  from  time  to  time 
as  appears  necessary.  The  homeopathic  vials  containing  small 
specimens  may  be  put  into  the  can  without  injury  to  the  other 
specimens.  Special  cans  of  various  sizes,  with  handles  and  screw 
covers,  are  made  for  naturalists.  One  of  these  cans  is  a  con- 
venient receptacle  for  carrying  the  alcohol  to  the  station  and 
for  receiving  the  collection  for  transportation.  Careful  notes 
should  be  made  on  the  spot  of  the  conditions  under  which  the 
species  are  found.  One  is  likely  to  forget  details  if  this  is  de- 
layed until  one  reaches  home.  Labels  should  be  used,  giving 
name  when  known,  or  a  number  when  the  name  is  not  known, 


COLLECTINa  15 

corresponding  witli  the  note-book.  Names  written  with  lead- 
pencil  on  a  slip  of  paper  will  not  be  defaced  by  or  injure  the 
alcohol.  Collections  when  arranged  permanently  should  be 
placed  in  glass  jars,  the  species  being  kept  separate. 

COLLECTING  AND   PRESERVING   SEAWEEDS 

To  collect  seaweeds  one  must  search  for  them  on  rocks,  in 
tide-pools,  in  the  sea- wrack  upon  the  beach,  on  piles  of  wharves, 
on  eel-grass,  and  on  the  surface  of  incoming  waves.  It  is  well  to 
follow  the  receding  tide  and  take  advantage  of  its  lowest  ebb 
(especially  of  that  of  the  spring-tides,  as  mentioned  above)  to 
search  the  extreme  limit  of  the  beach  in  the  short  time  it  is 
exposed.     Many  of  the  red  seaweeds  are  found  there. 

The  equipment  for  collecting  consists  of  a  basket,  two  small 
tin  pails,  one  small  enough  to  be  carried  within  the  other,  a  staff 
with  an  iron  edge  at  one  end  and  a  small  net  at  the  other,  and  a 
pocket-lens.  Rockweeds  {Fuciis)  or  other  coarse  gelatinous  sea- 
weeds should  be  put  into  the  basket.  The  pails,  half  filled  with 
sea-water,  will  receive  the  other  specimens,  fine  and  delicate  algae 
being  put  into  the  smaller  pail.  It  is  well  to  have  a  second  small 
receptacle  for  CaUithamnion  and  Griffithsia,  if  one  can  be  further 
burdened.  Desmarestia  should  be  kept  apart,  if  possible,  since  it 
discolors  and  decomposes  other  algae  j  it  should  also  have  the 
earliest  attention  when  the  time  comes  for  mounting,  and  salt 
water  should  be  used  for  floating  it  upon  the  mount,  otherwise 
the  beauty  of  the  specimen  will  be  impaired. 

Besides  its  use  as  a  support,  the  staff  is  needed  to  dislodge 
specimens  from  the  rocks,  and  the  net  to  secure  those  that  are 
floating  just  out  of  reach.  When  possible,  it  is  desirable  to  secure 
the  whole  plant,  including  the  holdfast,  and  to  gather  several 
plants  of  the  same  species,  since  they  vary  with  age  and  other 
conditions,  and  it  is  also  well  to  have  duplicates  for  exchange. 
It  is  particularly  desirable  to  obtain  plants  which  are  in  fruit. 
Each  specimen  as  it  is  taken  should  be  rinsed  in  the  sea- water  to 
free  it  from  sand. 

Collections  should  be  mounted  as  soon  as  convenient,  and 


16  INTRODUCTION 

especial  care  in  this  respect  should  be  taken  with  red  algae,  as 
they  decompose  quickly.  The  requisites  for  mounting  are 
blotters,  pieces  of  muslin,  two  or  more  smooth  boards,  weights, 
a  basin,  and  several  shallow  dishes  containing  water.  Fresh 
water  has  a  strong  action  on  the  color  and  substance  of  seaweeds, 
and  specimens  should  not  be  left  in  it  for  any  length  of  time. 

Lift  a  specimen  from  the  general  collection,  and  in  a  basin  of 
deep  water  carefully  wash  off  all  superfluous  matter ;  then  place 
it  in  shallow  water  and  spread  it  out,  trimming  it  judiciousl}^,  so 
that  when  mounted  it  will  not  be  too  thick  and  the  characteris- 
tics be  hidden.  Specimens  are  more  interesting  and  their  species 
more  easily  determined  when  laid  out  rather  thin,  showing  their 
branching  and  fruit.  After  the  specimen  is  thus  prepared,  place 
it  in  a  second  shallow  dish  of  water.  It  should  now  be  perfectly 
clean.  Float  it  out  into  the  desired  position,  spreading  it  well, 
letting  some  parts  show  the  details  of  the  branching,  and  other 
parts  the  general  natural  effect  of  the  mass.  Run  under  it  a 
rather  heavy  sheet  of  white  paper,  and  lift  it  carefully  from  the 
water.  If  raised  from  the  center,  it  is  easier  to  let  the  water 
subside  evenly  and  gradually  without  disarranging  the  parts. 
Some  collectors  find  it  better  to  float  the  specimen  in  water  deep 
enough  to  allow  the  left  hand  to  be  placed  under  the  sheet  to 
raise  it.  Lay  the  sheet  on  a  plate,  and  with  a  needle  or  forceps 
rearrange  any  of  the  delicate  parts  which  have  fallen  together. 
A  few  drops  of  water  placed  on  any  portion  will  usually  be  suffi- 
cient to  enable  one  to  separate  the  branchlets  or  ultimate  ramifi- 
cations.    A  magnifying-glass  will  be  useful  in  this  work. 

Cover  a  blotter  with  mounted  specimens,  spread  over  them  a 
piece  of  cotton  cloth,  and  on  this  place  another  blotter,  upon 
which  lay  more  mounted  specimens  and  a  cloth.  Proceed  in  this 
way  until  all  the  specimens  are  used.  Lay  the  pile  of  blotters 
between  boards,  and  on  them  place  the  weights.  The  weights 
should  not  be  very  heavy.  Judgment  must  be  used  in  assorting 
the  specimens,  those  that  are  fine  being  placed  together.  Those 
that  are  coarse  and  likely  to  indent  the  blotters  should  be  placed 
between  separate  boards.  In  this  way  a  flat  surface  and  an  even 
pressure  will  be  obtained.     The  blotters  and  cloths  should  be 


COLLECTING  17 

changed  twice  each  of  the  first  two  days,  then  the  cloths  should 
be  removed  and  the  specimens  left  in  press  for  a  week,  the 
blotters  being  changed  daily.  Be  sure  that  the  specimens  are 
perfectly  dry  before  placing  them  in  the  herbarium.  Label  each 
specimen  with  the  name  and  the  date  and  place  of  collection. 

There  are  some  seaweeds  which  cannot  be  treated  in  the  above 
manner.  Fucus  if  placed  in  fresh  water  soon  becomes  slimy. 
It  is  so  f uU  of  gelatine  that  it  soon  destroys  blotters  5  therefore 
it  is  well  to  hang  it  up  for  several  hours  and  then  place  it  between 
newspapers,  which  should  be  frequently  changed,  and  as  the 
plant  becomes  pliable  it  should  be  arranged  in  proper  position. 

Those  specimens  which  do  not  adhere  to  paper  in  drying  should 
be  secured  with  gum.  When  it  is  impossible  to  mount  speci- 
mens at  the  time  they  are  collected,  they  can  be  preserved  by 
drying ;  afterward  they  can  be  soaked  and  mounted  in  the  usual 
manner.  To  dry  the  plants,  lay  them  separately  upon  boards 
without  pressing  out  the  sea-water,  and  leave  them  in  an  airy, 
shaded  place  until  thoroughly  dry ;  then  pack  them  loosely  into 
boxes  and  label,  giving  date  and  locality.  Blotters  or  driers  can 
be  obtained  at  botanical-supply  stores  at  thirty-five  cents  per 
quire. 

HOW   TO   AERANGE   A  HERBARIIBI 

The  standard  herbarium-paper  is  sixteen  by  eleven  and  a  half 
inches.  The  sheets  are  single,  white,  smooth,  and  quite  heavy. 
These,  together  with  folded  sheets  of  yellow  manila  paper,  called 
genus-covers,  are  the  only  requisites.  It  is  desirable  to  have  also 
a  case  of  shelves  protected  by  glass  doors.  The  shelves  should 
be  twelve  by  eighteen  inches,  and  four  to  six  inches  apart.  They 
are  more  convenient  when  made  to  slide  like  drawers. 

The  different  species  of  one  genus  are  gummed  on  one  or  more 
of  the  white  sheets  and  placed  within  the  folded  manila  paper, 
which  serves  as  a  cover.  Each  specimen  should  be  signed  with 
its  name,  place,  and  date  of  collection,  thus : 

C.  nibrum.     Bar  Harbor.     Aug.  12,  1899, 

the  generic  name  being  indicated  by  its  initial  capital  letter  and 
the  specific  name  written  in  full.     To  this  are  often  added  the 


18  INTRODUCTION 

name  of  the  collector  and  some  interesting  comment.  On  the 
lower  left-hand  corner  of  the  genus-cover  is  written  the  generic 
name  in  full  and  the  species  of  that  genus  which  the  cover  con- 
tains, thus : 

r  G.  riibrum 
Ceramium  <  G.  strictum 

(  G.  diaphanum 

The  genera  of  an  order  are  then  placed  within  a  cover  and  labeled 
in  the  same  way,  the  legend  then  having  the  name  of  the  order 
on  the  left  and  the  genera  on  the  right  of  the  bracket,  thus : 

BliodymeniacecB,  r  GaTHthammon 
suborder       <  GriffitJisia 
Geramiece       v  Geramium 

When  the  order  is  a  large  one  the  genera  are  distributed  through 
as  many  covers  as  may  be  necessary.  The  covers  are  then 
arranged  on  shelves  in  the  regular  order  of  their  classification, 
and  each  shelf  is  labeled  with  the  order  it  contains.  Herbarium- 
sheets  cost  at  retail  one  dollar  per  hundred.  Genus-covers  cost 
at  retail  one  dollar  and  eighty  cents  per  hundred. 


Ill 

CLASSIFICATION 

THE  first  great  biological  division  is  into  kingdoms,  namely, 
the  animal  kingdom  and  the  vegetable  kingdom.  Then  by 
classification  the  vast  number  of  existing  animals  and  plants  are 
grouped  so  as  to  give  each  individual  a  definite  place.  By  this 
system  a  beautiful  order  is  established,  which  enables  the  student 
to  find  any  particular  animal  or  plant  he  may  wish  to  study,  and 
also  to  know  its  general  characteristics  from  the  name  of  the 
group  to  which  it  belongs. 

In  broad  generalization,  objects  of  wide  dissimilarity  are  rec- 
ognized as  belonging  to  the  same  kingdom,  as  do  trees  and 
grasses,  or  as  do  birds  and  fishes.  Certain  trees  or  grasses  and 
certain  birds  or  fishes  have  such  points  of  resemblance  that  they 
plainly  show  that  they  belong  to  subdivisions.  The  most  untu- 
tored people  recognize  these  distinctions,  but  the  naturalist  goes 
further  and  finds  points  of  distinction  which  the  casual  observer 
overlooks. 

The  animal  kingdom  has  a  varying  number  of  divisions,  called 
hrancJies,  suMingdoms,  or  pliyla.  Some  late  authors  have  admitted 
twelve  divisions,  and  have  given  them  the  name  phyla.  Each 
phylum  is  composed  of  a  group  of  animals  with  a  plan  of  struc- 
ture which  is  common  to  themselves,  but  differs  from  that  of  the 
animals  of  all  other  phyla. 

The  higher  animals  begin  with  the  twelfth  phylum,  namely, 
the  Chordafa,  or  vertebrates.  These  animals  have  a  spinal 
column,  or  series  of  vertebrae,  while  the  lower  animals,  or  inver- 
tebrates are  without  a  spinal  column,  and  depend  for  stability 

19 


20  INTRODUCTION 

upon  muscles  or  coriaceous  or  calcareous  coverings.  The  verte- 
brates are  first  represented  in  the  fish-like  forms.  Bilateral  sym- 
metry, however,  or  the  uniform  arrangement  of  parts  on  each 
side  of  a  central  axis,  exists  in  several  groups  which  are  below 
the  vertebrates,  the  first  pronounced  example  being  found  in 
worms.  Groups  lower  than  worms  have  their  organs  arranged 
around  a  central  axis  or  radiating  from  it,  and  were  once  all 
classed  as  radiates. 

An  animal  is  classified  in  accordance  with  its  morphology, 
anatomy,  histology,  and  embryology.  Morphology  determines 
its  general  shape,  the  position  of  its  limbs,  eyes,  and  mouth,  and 
the  covering  of  its  body ;  anatomy,  the  arrangement  of  its  internal 
organs,  such  as  the  position  of  its  heart,  lungs,  stomach,  etc. ; 
histology,  the  character  of  the  tissues  of  the  body ;  and  embry- 
ology, the  method  of  the  development  of  the  animal  from  the 
embryo  to  maturity.  It  is  only  after  these  exact  discriminations 
have  been  made  that  the  groups  are  arranged.  Owing  to  the 
greater  accuracy  resulting  from  histology  and  embryology 
(methods  which  have  been  employed  only  in  later  years),  many 
changes  in  classification  have  been  made,  and  as  science  advances 
will  continue  to  be  made. 

The  primary  groups  are  based  on  broad  general  characteristics, 
but  their  divisions  and  subdivisions  are  determined  by  closer 
distinctions.  Animals  having  shells  differ  from  those  having  a 
cartilaginous  or  those  having  a  crustaceous  covering,  and  are 
placed  in  different  groups.  Yet  mollusks  having  a  single  or  a 
double  shell,  having  spiral  or  flat  forms,  living  on  land,  in  fresh 
water,  or  in  the  sea,  while  differing  from  one  another,  are  all  of 
one  group.  Lobsters  and  crabs,  although  both  have  crustaceous 
coverings,  are  very  unlike ;  and  again,  there  are  many  species  of 
both  lobsters  and  crabs. 

To  group  individuals,  noting  resemblances  as  well  as  differ- 
ences, a  system  of  classification  has  been  arranged  with  the  fol- 
lowing divisions : 

Kingdom,  Phylum,  Class,  Order,  Family  (or  Suborder),  Genus, 
Species. 


IV 
ANIMAL  LIFE  IN  ITS  LOWEST  FORMS 

THE  biological  division,  or  discrimination,  between  animal 
and  vegetable  life,  is  based  on  the  manner  of  assimilating 
food.  Plants  feed  upon  mineral  substances,  or,  in  other  words, 
assimilate  inorganic  matter,  while  animal  life  requires  for  its 
support  vegetable  or  some  other  organic  matter. 

Animal  as  well  as  vegetable  life  in  its  lowest  forms  begins 
with  one-celled  organisms,  which  are  called  respectively  Protozoa 
(first  animals)  and  Protophyta  (first  plants).  Both  of  these  divi- 
sions are  composed  mostly  of  microscopic  objects,  and,  together 
with,  other  minute  forms  of  life  of  the  marine  species,  constitute 
a  great  part  of  the  planMon,  or  free-floating  organisms  of  the  sea. 
These  minute  organisms  seem  like  connecting-links  between  the 
two  kingdoms.  They  were  claimed  by  both  botanists  and  zoolo- 
gists until  the  use  of  the  microscope  made  close  observation  of 
minute  structure  possible. 

Among  the  small  animalcules  of  the  phylum  Protozoa  are  some 
which  are  familiar  to  all  by  name,  such  as  the  Infusoria,  which 
are  most  interesting  creatures  to  examine  in  a  drop  of  water 
under  the  microscope.  A  more  tangible  example  of  the  Protozoa 
are  the  Foraminifera.  Foraminifera,  like  diatoms,  have  a  shell- 
like covering,  and  these  shells,  among  the  most  plentiful  of  which 
are  those  of  the  genus  Glohigerina,  fall,  as  do  those  of  diatoms, 
in  immense  numbers  to  the  bottom  of  the  ocean,  and  form  re- 
spectively what  are  known  as  Glohigerina  and  diatomaceous  ooze. 
In  course  of  time  the  sedimentary  strata  become  fossilized ;  thus, 
the  stone  of  which  the  city  of  Paris  is  built  consists  of  fossilized 

21 


22  INTRODUCTION 

foraminifers,  and  tlie  pyramids  of  Egypt  are  built  of  nummulites, 
another  genus  of  Foraminifera.  It  is  estimated  that  an  ounce 
of  this  deposit  contains  four  millions  of  these  protozoans,  so  it  is 
impossible  to  conceive  the  numbers  of  once  living  animals  repre- 
sented in  the  tombs  of  the  Pharaohs.  Telegraph-cables  raised 
from  the  depth  of  two  miles  bring  the  message  to  naturalists 
that  the  bottom  of  the  ocean  at  that  depth  is  composed  of  little 
else  than  the  calcareous  shells  of  Foraminifera. 

Many  of  the  lower  animals  resemble  plants  in  form.  Hydroids 
and  polyzoans  are  often  gathered  and  preserved  as  seaweeds. 
Corals,  sea-anemones,  and  holothurians  are  curiously  like  plants. 
For  a  time  the  confusion  about  the  division  of  animals  and  plants 
was  partly  owing  to  this  resemblance  of  forms,  and  the  theory 
of  the  animal  nature  of  corals  was  for  a  long  time  considered  to 
be  refuted  by  the  testimony  of  a  naturalist  who  declared  that  he 
had  seen  them  in  bloom.  Later  this  class  of  animals  was 
believed  to  occupy  an  intermediate  sphere  and  partake  of  the 
characteristics  of  both  kingdoms.  The  name  zoophyte,  meaning 
"animal-plant"  or  '^mingled  life,"  w^as  adopted  because  of  these 
resemblances  and  was  formerly  applied  to  these  forms  only. 
To-day  it  has  a  broader  application.  There  is  still  a  neutral  class^ 
called  Protista,  comprising  organisms  which  have  not  yet  been 
classified  as  plants  or  animals. 


V 

DISTEIBUTION  OF  ANIMAL  LIFE  IN  THE   SEA 

ALL  living  things  which  inhabit  the  sea  have  their  appointed 
J\  boundaries,  and  the  localization  of  marine  life  is  as  distinct 
as  is  that  of  terrestrial  life.  Each  kind  of  beach  has  forms  of  life 
peculiar  to  itself.  Those  animals  which  inhabit  rocky  shores  or 
stony  beaches  or  sand  or  mud  may  be  looked  for  anywhere  under 
similar  physical  surroundings.  They  are,  however,  modified  by 
climatic  conditions,  and  in  wide  ranges  differ  in  genera  and 
species.  The  rocky  coast  of  Maine  has  a  class  of  sea-urchins  and 
starfishes  which  are  different  from  those  which  live  on  the  rocky 
shores  of  the  northern  Pacific  coast,  yet  they  are  all  easily  recog- 
nized as  belonging  to  the  same  family,  and  a  description  of 
typical  forms  is  a  sufficient  guide  to  the  recognition  of  their 
relationships. 

A  bathymetrical  division  defines  the  classes  of  animals  accord- 
ing to  the  depth  of  water  in  which  they  live.  Those  which  live 
near  the  shore  are  littoral  species,  those  of  the  broad  sea  are 
pelagic,  while  those  living  at  great  depths  are  abyssal. 

Their  modes  of  life  are  distinguished  by  other  terms.  Those 
which  float  at  or  near  the  surface  and  are  carried  about  by  the 
currents,  like  the  jellyfishes  and  the  minute  organisms  mentioned 
elsewhere,  are  x>lanliton.  Strong  swimming  animals  which  move 
about  at  will  are  neMon.  Those  which  are  fixed,  like  oysters, 
sponges,  etc.,  and  those  which  crawl  on  the  bottom,  like  crabs, 
echinoderms,  etc.,  are  benthos. 

Again,  geographical  divisions  are  named,  in  recognition  of 
climatic  influences.     The  boreal  fauna  and  flora  on  the  Atlantic 

23 


24  INTRODUCTION 

coast  extend  from  Cape  Cod  northward;  tlie  American,  from 
Cape  Cod  to  Cape  Hatteras ;  the  West  Indian,  from  Cape  Hatte- 
ras  southward.  On  the  Pacific  coast  the  divisions,  without  defi- 
nite names,  are  from  the  Isthmus  to  Acapulco,  Acapulco  to  the 
Gulf  of  California,  Cape  Lucas  to  the  Strait  of  Fuca.  These 
divisions  merge  at  indefinite  lines,  but  the  above  limits  are 
generally  accepted  as  the  points  of  broad  division. 

The  shore  or  littoral  fauna  is  especially  abundant  and  com- 
prises more  species  that  are  curious  in  form  and  beautiful  in 
color  than  the  others.  The  invertebrates  of  the  deep  sea  are 
mostly  transparent  and  of  a  blue  or  violet  tint,  while  the  fishes 
are  gray  or  bluish  above  and  white  beneath,  which  renders  them 
inconspicuous  to  their  enemies. 


VI 
SOME   BOTANICAL  FACTS  ABOUT  ALa^ 

THE  vegetable  world  is  separated  into  two  great  divisions: 
thallopliyteSj  or  plants  having  no  distinction  of  leaf  or  stem, 
and  cormopliytes,  or  plants  w^hich  have  leaves  and  stems.  All 
thallophytes  that  live  in  the  water  and  are  nourished  wholly  by 
water  are  called  algm. 

A  second  great  division  of  plants  is  into  cryptogams,  or  those 
that  have  no  flowers,  and  phanerogams,  or  those  that  have  flowers, 
by  means  of  which  seeds  are  produced  and  successive  generations 
of  plant  life  continued. 

ThaUopliytes  and  cryptogams  comprise  the  lowest  and  simplest 
vegetable  organisms.  Algge  belong  to  both  these  divisions;  to 
the  first  because  they  have  neither  stems  nor  leaves,  and  to  the 
second  because  they  have  no  flowers. 

The  lowest  forms  of  algee  are  microscopic  in  size,  each  indi- 
vidual being  a  single  cell  5  but  in  the  ascending  scale  they  attain 
curious  and  beautiful  shapes,  some  growing  to  a  gigantic  size 
and  in  forms  that  resemble  shrubs  and  trees.  The  green  surface 
commonly  seen  on  the  shady  side  of  trees,  on  stone  steps,  and 
in  other  damp  places  is  one  of  the  species  of  algae  which  consist 
of  a  single  cell.  This  plant  or  cell  divides,  and  the  separate  divi- 
sions divide  and  subdivide  again  and  again,  and  in  time  the 
aggregate  number  is  great  enough  to  spread  over  a  comparatively 
large  surface,  and  thus  become  visible  to  the  naked  eye.  This 
plant,  the  Fleiirococcus  vulgaris,  is  a  fresh- water  alga.  The  Fro- 
tococcus  nivalis,  or  red  snow,  described  on  page  33,  is  a  closely 
allied  species.     The  green  and  blue-green  scums  and  slimes  on 

25 


26  INTRODUCTION 

brackish  ditches  and  on  the  stones  and  woodwork  of  wharves  are 
also  species  of  the  lowest  orders  of  algae  and  increase  by  cell- 
division.  Many  of  them  are  in  colonies  incased  in  gelatinous 
matter.  These,  together  with  plants  of  a  little  higher  order, 
though  still  of  low  organization,  the  Confervacece,  form  a  large 
part  of  the  green  vegetation  between  tide-marks. 

The  vegetative  body  of  a  thallophyte  is  a  thallus,  and  corre- 
sponds to  stem  and  leaf.  It  is  also  called  a  frond.  What 
corresponds  to  the  root  of  flowering  plants  is  in  algae  a  disk  or 
conical  expansion  of  the  base  of  the  plant.  It  is  simply  a  hold- 
fast by  which  the  frond  attaches  itself  to  any  submerged  material. 
The  algge  which  grow  on  sandy  shores  and  on  corals  have  hold- 
fasts which  branch  like  fibrous  roots  and  penetrate  porous  sub- 
stances in  all  directions;  but  this  is  only  for  greater  stability, 
and  is  an  adaptation  to  the  habitat.  Holdfasts  do  nothing  for 
algae  other  than  the  name  implies,  whereas  real  roots  absorb  the 
nourishment  upon  which  plants  live.  Algae  are  nourished  by  the 
substances  held  in  solution  by  the  water  which  surrounds  them. 

Algae  are  the  lowest  and  simplest  in  organization  of  all  plants, 
because  they  are  composed  of  but  one  class  of  cells,  such  as  in 
flowering  plants  are  called  the  parencJiyma,  or  soft  cells,  these 
being  the  ones  which  compose  the  pulp  of  the  leaf.  In  the  lowest 
orders  of  algae  single  cells  constitute  individual  plants,  as  in 
Pleurococciis ;  but  in  the  higher  forms,  such  as  Sargassum,  they 
arrange  themselves  in  such  a  variety  of  combinations  as  to  re- 
semble plants  which  have  leaf  and  stem.  The  botanical  distinc- 
tion is  that  in  leaf  and  stem  there  would  exist  the  woody  and  the 
vascular  cells  as  well  as  the  parenchyma  cells. 

Beginning  with  plants  composed  of  a  single  cell,  the  next 
development  is  into  filamentous  plants,  which  are  single  thread- 
like rows  of  cells,  as  in  Cladophora.  In  Ulva  is  seen  the  earliest 
type  of  an  expanded  leaf.  The  cells  are  here  arranged  in  a  hori- 
zontal surface  of  plate-like  or  ribbon-like  shape. 

In  Ulva  there  is  a  double  layer  of  cells.  The  layers  separate 
in  Enteromorpha^  giving  a  hollow  or  tubular  form.  In  Monos- 
troma  a  double  layer  is  opened  or  torn  apart,  giving  a  frond  with 
a  single  layer  of  cells. 


SOME  BOTANICAL  FACTS  ABOUT  ALG^       27 

The  stem-like  forms  of  certain  algae  are  composed  of  cylindrical 
cells  which  combine  or  grow  in  a  longitudinal  direction  chiefly. 
Sometimes  the  cells  are  arranged  evenly,  in  which  case  the  stem 
seems  articulated,  as  in  some  species  of  Ceramium.  Again,  they 
are  irregularly  placed,  so  that  the  stem  appears  solid. 

The  highest  types  of  algae  in  the  differentiation  of  parts,  or 
vegetative  forms,  are  to  be  found  in  the  Fucacece,  of  the  brown 
seaweeds;  the  highest  in  the  reproductive  development,  in  the 
red  class. 

Reproduction  by  cell-division,  in  which  the  organism  itself 
breaks  up  into  two  or  more  individuals,  is  called  vegetative  repro- 
duction. Higher  forms  reproduce  by  spores,  or  germ-cells,  which 
give  rise  to  new  individuals  on  germination. 

The  substance  of  an  alga  is  more  or  less  firm,  according  as  the 
vegetable  mucus  or  gelatinous  matter  it  contains  has  more  or  less 
consistency;  it  is  membranaceous  when  the  gelatine  is  scant  and 
glossy,  gelatinous  when  it  is  abundant  and  fluid,  and  cartilaginous 
when  it  is  hard. 

Some  algge  are  annuals ;  a  few  are  perennials,  and  cast  off  and 
renew  their  laminae  every  season.  Many  plants  present  quite  a 
different  appearance  at  different  seasons  of  the  year,  and  so  are 
often  difficult  to  identify.  Those  which  form  spores  throw  off 
these  isolated  cells,  which  sink  or  are  washed  to  positions  where 
they  germinate  and  begin  their  cycle  of  life.  Many  of  the  spores 
begin  their  growth  at  once,  without  regard  to  season,  so  the 
species  is  ever  present. 


VII    * 
NAMINa  OF  PLANTS 

THE  real  or  technical  names  of  plants,  which  at  first  appear 
long  and  unpronounceable,  are  in  reality  simple  when  the 
system  of  naming  is  understood.  Every  plant  has  Si  generic  and 
a  specific  name.  The  generic  name  is  analogous  to  the  surname  of 
a  person,  such  as  Smith  or  Jones.  The  specific  name  is  analogous 
to  the  Christian  name  of  a  person,  such  as  John  or  James.  The 
specific  name  never  stands  alone,  and  would  have  as  little  desig- 
nating character  as  John or  James . 

This  is  called  the  Unomial  (two-name)  nomenclatnre.  It  was 
introduced  by  Linnaeus,  and  greatly  simplified  the  system  of 
naming.  The  rule  in  scientific  nomenclature  is  that  all  names 
must  be  Latin  or  Latinized.  This  gives  a  universal  language  by 
which  scientists  of  all  countries  understand  one  another. 

The  names  of  classes  (the  highest  groups)  and  subclasses  are 
adjectives  or  adjective  nouns,  expressing  the  most  prominent 
characteristic  of  the  class  or  subclass.  Thus  the  four  subclasses 
of  the  class  Algm  are  : 

CyanopMjcem  (subclass  of  blue-green  alg«). 

Clilorophycem  (subclass  of  grass-green  algae). 

Flueophycem  (subclass  of  dusky-brown  or  olive-green  algae). 

Ehodophycem  or  Floridece  (subclass  of  red  siigse). 

Orders  are,  with  few  exceptions,  the  names  of  genera  with  the 
termination  -acece,  as : 

Ulvacece,  from  the  genus  Ulva. 

FJctocmpacece,  from  the  genus  Ectocarpus. 

GigartinacecB,  from  the  genus  Gigartina. 

28 


NAMING  OF  PLANTS  29 

Suborders,  or  groups  between  orders  and  genera,  terminate  in 
-em.  Names  of  genera  are  nouns  or  words  taken  as  nouns.  They 
are  derived  from  any  source,— from  prominent  or  peculiar  char- 
acteristics, from  localities,  or  from  names  of  botanists,— or  they 
may  be  wholly  arbitrary.  Personal  generic  names  are  divested 
of  titles  and  take  a  final  a,  or,  in  many  cases,  for  euphony,  ia. 
Thus,  TJlva  is  the  Latin  for  "  sedge '' ;  Uctocarpus  is  from  two 
Greek  words  meaning  "fruit  outside'';  CoralUna  means  "coral- 
like " ;  GrinneUia  is  named  for  Mr.  Henry  Grinnell. 

The  specific  names  are  commonly  adjectives,  but  sometimes 
they  are  nouns,  and  occasionally  are  the  names  of  the  botanists 
who  first  described  the  plants,  in  which  case  the  name  terminates 
in  4  or  -ii.  The  specific  name  always  follows  the  generic  name, 
thus: 

Ectocarpus  Hooperi,  a  species  of  Ectocarpus,  first  described  by 
Mr.  Hooper. 

GrinneUia  Americana,  a  species,  peculiar  to  America,  of  a  genus 
named  for  Mr.  Grinnell. 

Griffithsia  corallina,  a  species  resembling  coral,  and  belonging 
to  a  genus  named  for  Mrs.  Griffiths. 

With  regard  to  the  four  subclasses  mentioned  above,  it  should 
be  said  that  algae  are  strictly  classified  in  accordance  with  their 
methods  of  reproduction ;  but  since  allied  species  have,  with  few 
exceptions,  the  same  color,  the  classification  by  colors  is  generally 
adopted  as  convenient  and  sufficiently  precise. 

Familiar,  or,  in  technical  language,  "  vulgar,''  names  are  very 
generally  given  to  land  plants,  and  especially  to  flowers  ;  but  sea- 
weeds are  less  in  sight  than  flowers  are,  and  so,  save  in  a  few 
instances,  have  not  been  named  except  by  the  man  of  science. 
To  remember  the  scientific  names  will  not  be  found  difficult,  for 
without  effort  or  special  pains  to  acquire  the  new  vocabulary, 
the  names,  like  those  of  new  personal  friends,  will  insensibly 
become  fixed  in  the  memory. 

In  the  body  of  this  work  each  of  the  groups  (class,  subclass, 
order,  etc.),  in  the  classification  of  both  animals  and  plants,  is 
indicated  by  a  special  kind  of  type. 


VIII 
DISTRIBUTION  OF  ALaM 

THE  eastern  coast  of  North  America  has  been  divided  into 
four  sections,  which  correspond  to  the  distribution  of  the 
algaB  which  are  characteristic  of  each  section.  The  boundary- 
lines  are  not  precise,  since  some  species  of  each  section  extend 
beyond  the  defined  limits;  but  arctic  forms  are  not  generally 
found  south  of  Cape  Cod,  nor  can  tropical  varieties  be  expected 
north  of  Cape  Hatteras.  On  the  intervening  coast,  however,  there 
are  some  species  common  to  both  sections.  The  divisions  are : 
(1)  Greenland  to  Cape  Cod ;  (2)  Cape  Cod  to  Cape  Hatteras ;  (3) 
Cape  Hatteras  to  Cape  Florida;  (4)  the  Florida  Keys  and  the 
shores  of  the  Gulf  of  Mexico. 

On  the  Pacific  coast  such  distinct  lines  of  demarcation  do  not 
exist,  there  being  no  such  natural  barriers  as  are  formed  on  the 
eastern  coast,  first  by  Cape  Cod,  and,  second,  by  the  stretch  of 
sand-beach  which  extends  from  New  York  to  Charleston,  and 
which  divides  sharply  the  climatic  varieties. 

The  whole  shore  is  again  divided  laterally  into  three  distinct 
belts,  called  the  littoral,  the  lamincman,  and  the  coralline  zones. 
The  first  or  littoral  zone  covers  the  space  between  tide-marks. 
Vegetable  life  in  this  zone  is  subjected  first  to  exposure  to  the 
sun  and  air,  and  even  to  desiccation,  and  then  to  entire  sub- 
mergence at  constantly  recurring  periods.  The  rockweeds  (Fucus), 
which  are  so  plentiful  in  this  zone,  are  very  gelatinous,  nature 
having  apparently  provided  the  gelatine  to  protect  the  cells  of 
the  plant  from  the  effects  of  the  alternating  extreme  conditions. 
Fucus  and  FnteromorpJia  predominate  in  this  zone. 

30 


DISTRIBUTION  OF  ALG^  31 

The  laminarian  zone  extends  from  low- water  mark  to  the  depth 
of  fifteen  fathoms.  The  Laminariacece  and  the  beautiful  red  algge 
(FhridecB)  grow  here. 

The  third  or  coralline  zone  extends  to  the  depth  of  about  fifty 
fathoms.  The  algae  of  this  zone,  the  nullipores,  are  incrusted 
with  a  deposit  of  lime  which  gives  them  the  appearance  of  corals ; 
and,  singularly  enough,  the  corals,  which  are  animal  forms, 
simulate  plant  life. 

Again,  algee  have  special  habits  and  demand  certain  climates 
and  seasons  for  their  growth.  Algologists  register  the  place 
where  a  specimen  is  found,  and  in  this  way  localities  have  been 
pretty  well  determined.  However,  great  exactness  has  not  been 
reached,  and  the  collector  is  ever  watchful  to  find  an  alga  in 
some  undiscovered  home  within  the  given  range.  Although 
algae  grow  from  extreme  high- water  mark  to  the  depth  of  fifty 
fathoms,  almost  every  variety  may  be  found  on  the  beach,  those 
growing  in  deep  water  being  frequently  torn  off  and  washed 
ashore  by  the  waves.  The  heaps  of  sea- wrack  will  often  reward 
one  who  examines  them  carefully  for  deep-water  species.  Sea- 
weeds are  most  abundant  on  rocky  shores,  particularly  where 
there  are  stratified  rocks  with  crevices,  which  afford  shelter  from 
the  waves.  Rock  pools  often  contain  beautiful  varieties  of  the 
more  delicate  species.  Red  algse  will  sometimes  be  found  on 
the  shady  side  of  these  pools.  Sand-beaches  are  unfavorable 
to  the  growth  of  seaweeds,  but  fronds  which  have  been  carried 
long  distances  by  the  currents  will  frequently  be  found  on  such 
shores. 


IX 

SOME  PECULIAR  AND  INTERESTINa 
VARIETIES  OF  ALO^ 

THE  species  of  seaweeds  that  are  known  and  classified  are 
said  to  number  several  thousands.  These  plants,  which 
have  neither  vessels  for  the  conduction  of  fluids,  nor  fibers,  con- 
sisting simply  of  the  first  vegetable  element,  the  cell,  have,  not- 
withstanding this  limitation,  assumed  a  great  variety  of  forms. 
In  size  they  vary  from  one  one-thousandth  of  an  inch  in  diameter, 
the  smallest  green  plants  known,  to  those  which  exceed  in  length 
the  height  of  the  tallest  trees  and  form  dense  submarine  forests, 
which  in  places  make  comparatively  deep  water  impassable  for 
boats.  In  texture  they  vary  from  a  jelly-  to  a  paper-  and  a 
leather-like  consistency.  In  color  they  have  all  the  shades  of 
green,  brown,  and  red. 

DIATOMS  AND   OTHER  MINUTE  ALG^ 

Among  the  smallest  siigse  are  diatoms.  They  are  microscopic 
in  size,  but  exist  everywhere  in  both  salt  and  fresh  water,  and 
are  infinite  in  variety  as  well  as  in  numbers.  They  have  a  sili- 
cious,  shell-like  covering,  which  divides  and  subdivides  in  their 
reproductive  growth,  forming  varied  shapes  which  are  exceed- 
ingly beautiful  and  interesting  to  examine  under  the  microscope. 
In  vast  numbers  they  float  on  the  surface  of  the  sea,  and, 
together  with  other  minute  free-floating  organisms,  form  the 
basis  of  food-supply  for  fishes.  Their  indestructible  shells  fall 
to  the  bottom  of  the  sea,  forming  large  deposits,  which  in  time 
become  fossiUzed.     The  city  of  Richmond,  Virginia,  is  built  upon 

32 


SOME  PECULIAR  VARIETIES  OF  ALGM  33 

a  fossiliferous  bed  of  diatoms,  which  measures  twenty  to  eighty 
feet  in  depth  and  several  miles  in  length. 

Associated  with  diatoms,  in  fresh  water,  are  desmids,  which 
are  green  in  color  and  resemble  the  diatoms  except  in  having  a 
cartilaginous  instead  of  a  silicious  covering.  Another  minute 
organism,  Pyrocystis  noctUuca,  is  luminous  and  is  said  to  produce 
the  beautiful  phosphorescent  effects  seen  in  tropical  seas.  Tri- 
chodesminm  is  a  little  alga  which  periodically  occurs  in  great 
numbers,  giving  the  water  a  red  appearance,  as  in  the  Red  Sea, 
which  is  said  to  derive  its  name  from  this  circumstance. 

RED   SNOW 

In  the  high  latitudes  of  the  arctic  regions,  also  on  snowy  moun- 
tains at  altitudes  where  all  vegetable  life  is  supposed  to  be 
extinguished,  there  sometimes  appears  a  redness  on  the  surface 
of  the  snow,  which  in  some  cases  extends  for  many  miles.  At  a 
certain  place  in  Greenland  the  color  was  so  vivid  that  an  arctic 
voyager  named  the  locality  the  Crimson  Bluffs. 

The  strangeness  and  almost  sudden  appearance  of  this  color  in 
the  snow  have  been  so  unaccountable  to  uninformed  observers 
that  it  has  been  ascribed  by  them  to  the  falling  of  bloody  snow 
and  has  been  regarded  with  superstition.  The  redness  is  caused 
by  the  growth  of  one  of  the  smallest  of  plants,  the  Protococcus 
nivalis.  It  is  a  simple  one-celled  alga  containing  protoplasm 
and  endochrome  (red  coloring-matter).  It  grows  by  cell-division, 
the  cell  dividing  into  four,  eight,  or  sixteen  parts  on  a  quaternary 
scale.  Each  part  acquires  a  new  covering  while  within  the 
mother  cell,  and  when  it  emerges  it  is  a  complete  individual 
and  ready  to  repeat  the  process.  Only  a  few  hours  are  required 
for  its  growth  and  development ;  hence  its  increase  is  rapid,  and 
it  requires  but  a  little  time  to  make  itself  manifest  in  those  places 
where  the  conditions  are  favorable  to  its  existence. 

THE    SARGASSO    SEA 

When  the  voyager  reaches  a  certain  region  of  the  North  Atlan- 
tic, called  the  Sargasso  Sea,  he  sails  into  a  vast  undulating  marine 


34  INTRODUCTION 

prairie.  Farther  than  the  eye  can  reach  is  spread  a  yellowish- 
brown  vegetation  which  covers  the  water  as  grass  covers  the 
plain.  Sometimes  these  weeds  are  so  thick  as  to  impede  navi- 
gation, and,  seen  from  a  little  distance,  seem  substantial  enough 
to  walk  upon.  At  other  times,  according  to  seasons  and  condi- 
tions of  storm  and  wind,  they  are  divided  into  strips  or  into 
island-like  masses,  with  spaces  of  clear  water  between.  If  the 
sailor  did  not  know  the  special  conditions  existing  here  he  might 
suppose  he  had  come  upon  dangerous  shallows ;  or  were  the 
waters  less  turbulent  he  might  dream  that  he  was  floating 
among  the  water-weeds  of  an  inland  lake. 

This  vast  acreage  of  vegetation,  as  large  as  the  continent  of 
Europe,  lying  southwest  of  the  Azores  and  extending  between 
the  Canary  and  the  Cape  Verde  Islands,  was  first  reported  by 
Columbus,  and  takes  its  name  from  the  floating  plant  of  which  it 
is  composed,  the  Sargassum  hacciferum,  a  species  of  the  order 
Fucacece,  commonly  known  as  gulfweed.  Columbus's  sailors  took 
fright  at  the  marvelous  appearance  and  wished  to  turn  back, 
thinking  they  had  reached  the  end  of  the  navigable  ocean.  They 
thought,  if  land  were  beyond,  it  was  guarded  by  shoals,  and  that 
the  weeds  concealed  dangerous  rocks.  Columbus  threw  out  two 
hundred  fathoms  of  line,  but  did  not  reach  bottom,  and  con- 
tinued on  his  course  for  fifteen  days  before  emerging  into  clear 
water.  From  that  day  to  this  the  Sargasso  Sea  has  attracted  the 
attention  of  all  navigators.  It  is  especially  interesting  to  scien- 
tists. The  physicist  finds  there  the  phenomenon  of  the  ocean 
currents  holding  in  a  vortex  this  immense  mass  of  seaweed,  the 
zoologist  finds  a  great  pasture  in  whose  protecting  shelter  are 
living  and  breeding  countless  numbers  of  marine  animals,  and 
the  botanist  is  puzzled  because  the  source  of  this  species  of  plant 
is  clouded  with  doubt. 

According  to  one  theory,  the  plants  are  dislodged  by  the  tem- 
pests from  terrestrial  beds  and  carried  by  the  Gulf  Stream  into 
the  huge  eddy ;  but  since  there  does  not  exist  enough  of  the 
attached  plants  of  this  species  to  supply  the  vast  accumulation, 
another  and  more  generally  accepted  theory  is  that  the  gulfweed 
lives  also  a  pelagic  life  and  adapts  itself  to  the  conditions  of  the 


Agarura  Tumeri. 


PLATE    II. 
Macrocystis  pyrifera. 


Nereocystis  Llitkeana. 


SOME  PECULIAR  VARIETIES  OF  ALG^  35 

floating  state,  thus  dispensing  with  the  disk-Hke  root,  as  it  needs 
no  holdfasts,  and  propagating  solely  by  lateral  and  axillary 
ramification. 

There  are  said  to  be  one  hundred  and  fifty  species  of  Sargas- 
sum,  but  )S.  haeciferum  alone  constitutes  the  beds  of  the  Sargasso 
Sea.  The  plant  is  the  most  highly  differentiated  of  any  seaweed, 
in  that  it  more  nearly  approaches  the  true  leaf  and  stem,  and  is 
described  botanically  as  follows :  Frond  furnished  with  distinct, 
stalked,  nerveless  leaves  and  simple,  axillary,  stalked  air-vessels. 
The  integument  is  leathery,  and  the  color  brown  of  varying 
shades.  The  most  striking  peculiarity  is  the  abundance  of 
globular  cells.  These  berry-like  air-bladders  give  the  plant  buoy- 
ancy enough  to  support  the  weight  of  its  innumerable  guests. 
(Plate  XVI.) 

THE   LAMINARIACE^ 

In  the  laminarian  zone,  described  above,  grow  the  Laminaria- 
cece,  an  order  of  brown  seaweeds,  some  of  whose  genera  grow  to 
enormous  size,  and  in  some  places  form  dense  submarine  forests. 
Darwin  speaks  of  the  good  service  rendered  by  these  plants  to 
vessels  navigating  stormy  coasts,  where  often  they  act  as  natural 
breakwaters,  and  again  as  buoys  designating  dangerous  rocks 
near  the  shore  on  which  they  grow.  The  seaweeds  belonging  to 
this  order,  commonly  known  as  oarweeds,  tangle,  devil's-apron, 
and  sea-colander,  are  frequently  seen  twelve  to  twenty  feet  in 
length,  and  others  are  measured  by  fathoms.  One  of  the  giant 
plants  is  Nereocystis  Lutkeana,  which  occurs  on  the  northwest 
coast.  It  has  a  stalk,  sometimes  three  hundred  feet  in  length, 
which  bears  on  its  extremity  a  barrel-  or  cask-shaped  air-vessel, 
six  or  seven  feet  long,  from  the  surface  of  which  a  tuft  of  fifty 
or  more  forked  laminae  grows  to  a  length  of  thirty  or  forty  feet. 
The  stem  which  anchors  this  immense  frond  is  so  small  that  the 
Aleutian  Indians  use  it  for  fishing-lines.  The  sea-otter  makes 
his  home  on  its  huge  air-vessel,  and  the  plant  is  called  by  the 
Russians  the  '^  sea-otters'  cabbage." 

But  the  longest  of  all  known  plants  is  the  alga  Macrocystis.  Its 
thin  naked  stem,  the  diameter  of  which  seldom  exceeds  one  quar- 


36       '  INTRODUCTION 

ter  of  an  inch,  is  reported  by  one  author  to  be  seven  hundred  feet 
in  length,  by  another  fifteen  hundre '  feet.  It  is  terminated  by 
a  lamina  fifty  feet  long,  resembling  a  pinnatifid  leaf,  each  leaflet 
of  which,  at  its  point  of  division  on  the  stem,  expands  into  an 
air-vessel  as  large  as  an  egg.  These  air-vessels  sustain  the 
immense  frond  which  floats  on  the  surface  of  the  water,  its  leaf- 
lets depending  in  a  vertical  position  from  the  stem.  31.  pyrifera, 
the  only  species,  is  found  in  the  Southern  oceans  and  on  the 
Pacific  coast  of  North  America. 

Lessonia,  another  genus,  resembles  a  palm-tree.  It  grows 
erect  to  a  great  height  and  has  a  stem  like  the  bole  of  a  tree. 
It  branches  in  a  forking  manner  and  has  depending  from  its 
branches  laminae  two  or  three  feet  long.  The  large  stems  from 
which  the  laminge  have  been  torn  by  the  storms,  and  which  have 
been  cast  ashore  on  the  Falkland  Islands,  as  described  by  Sir 
Joseph  Hooker,  resemble  driftwood,  as  they  lie  in  piles  three  or 
four  feet  high  and  extending  for  many  miles. 

Agartmi  and  Thalassiophyllum  are  arctic  genera,  but  they  are 
found  within  our  limits,  the  former  in  the  North  Atlantic.  It 
has  a  simple  but  enormous  leaf -like  frond.  The  latter,  which  is 
found  on  the  North  Pacific  coast,  has  a  compound  frond.  Both 
are  characterized  by  their  fronds  being  perforated  throughout 
with  holes,  giving  them  the  name  of  sea-colander. 


USES  OF  AhGM 

WATER  covers  two  thirds  of  the  surface  of  the  earth,  and 
algee,  with  a  very  few  exceptions,  constitute  the  whole 
vegetation  which  exists  in  that  enormous  area.  They  have, 
therefore,  an  important  part  to  perform  in  the  economy  of 
nature.  Alg^  do  not,  like  land  plants,  derive  their  nourishment 
from  the  soil  to  which  they  are  attached,  but  from  substances 
held  in  solution  by  water.  In  their  growth  they  effect  changes 
in  the  water  analogous  to  those  effected  by  land  plants  in  the 
air ;  that  is,  they  change  so-called  impurities  in  the  water  into 
materials  essential  to  animal  life.  The  function  of  plants  is  that 
of  transforming  or  manufacturing  inorganic  matter,  which  they 
assimilate,  into  organic  matter  (such  as  starch,  albumen,  sugar), 
which  forms  their  own  structure  and  which  is  the  food  essential 
to  animals.  In  this  process,  plants  inhale  carbonic  acid  gas 
which  animals  breathe  out,  and  exhale  oxygen  which  animals 
breathe  in.  Plants  feed  on  mineral  substances  and  furnish  vege- 
table food,  thus  keeping  up  the  balance  of  life. 

Fresh- water  algae,  have  a  like  economic  value.  The  green  sur- 
face on  stagnant  pools  is  a  vegetable  growth  whose  function  is 
to  assimilate  the  matter  which  makes  the  pool  offensive.  A 
submerged  district  soon  becomes  covered  with  scum,  or  minute 
plants  {SpliCBoplea  annuUna),  which  grow  with  great  rapidity,  using 
up  the  materials  of  the  decaying  vegetation,  and  in  great  measure 
counteracting  the  ill  effects,  in  the  atmosphere,  of  such  decay. 
When  the  waters  subside,  the  plants  shrivel  up  and  appear  like 
thin  paper  covering  the  ground.     This  ephemeral  substance  soon 

37 


38  INTRODUCTION 

disappears,  without  giving  evidence  of  its  nature  in  dust  or 
gases,  its  body  seeming  to  be  a  macliine  which  transmutes,  but 
does  not  hold,  the  substances  on  which  it  grows. 

Algae,  as  has  been  said  above,  grow  in  definite  zones,  and  each 
zone  has  also  a  definite  animal  life  which  finds  there  its  food. 
Darwin  says :  '^  In  all  parts  of  the  world  a  rocky  and  partially 
protected  shore  perhaps  supports  in  a  given  space  a  greater 
number  of  individual  animals  than  any  other  station."  And 
speaking  of  the  Laminariacece,  he  adds :  ^^  I  can  only  compare 
these  great  aquatic  forests  of  the  southern  hemisphere  with  the 
terrestrial  ones  in  the  intertropical  regions.  Yet  if  in  any 
country  a  forest  was  destroyed  I  do  not  believe  nearly  so  many 
species  of  animals  would  perish  as  would  here  from  the  destruc- 
tion of  the  kelp."  The  same  may  be  said  of  the  Sargasso  Sea, 
where  millions  of  living  creatures  make  their  home.  In  every 
kind  of  marine  fauna  there  are  species  which  derive,  if  not  the 
whole,  at  least  a  part  of  their  nourishment  from  the  seaweeds. 

The  vegetation  in  the  narrow  boundary  of  the  three  zones  is 
palpably  inadequate  to  supply  the  needs  of  the  animal  life  which 
exists  in  deeper  waters.  But  over  the  broad  area  of  the  ocean 
there  exists  a  vast  number  of  pelagic,  free-floating  algSB,  which, 
although  microscopical  in  size,  are  almost  infinite  in  numbers. 
In  illustration  of  this  it  has  been  estimated  that,  although  they 
are  not  especially  numerous  in  the  Sargasso  Sea,  yet  if  all  the 
seaweed  there  were  gathered  into  one  mass  and  the  free-floating 
algae  into  another,  the  bulk  of  the  latter  would  exceed  that  of  the 
former.  The  pelagic  flora  consists  of  Diatomacece,  Protococcacece, 
PeridiniecB,  and  others.  Undoubtedly  it  is  on  these  pastures  that 
fishes  feed,  as  well  as  other  organisms  which  in  turn  are  food  for 
fishes. 

Fucus  and  Laminaria  constitute  the  kelp  from  which  iodine  is 
obtained,  and  were  at  one  time  the  source  of  the  potash  of  com- 
merce. Fuciis  vesiculosus  is  a  constituent  of  a  medicine  used  as  a 
cure  for  obesity.  Chondrus  crispus,  commonly  known  as  Irish 
moss,  was  a  few  years  ago  generally  used  as  an  article  of  diet. 
Porphyra  vulgaris  (laver)  is  used  by  the  Chinese  for  soups.  Blio- 
dymenia  palmata  (dulse)  is  an  article  of  food  in  Ireland  and  Scot- 


USES  OF  ALG^  39 

land.  Gracilaria  spinosa  is  used  by  birds,  allied  to  the  swallows, 
for  making  their  nests— the  edible  nests  found  in  large  numbers 
on  the  islands  of  the  Indian  Archipelago,  especially  in  the  caves 
on  the  shores  of  Java,  and  gathered  and  sent  to  China,  where 
they  bring  large  prices  and  are  used  in  making  the  famous  birds'- 
nest  soup.  Gracilaria  Uchenoides,  also  a  species  of  the  Eastern  seas, 
is  the  source  of  agar-agar,  a  preparation  used  in  laboratories  as  a 
culture-medium  for  bacteria.  Fossil  diatoms  are  ground  and 
used  for  polishing-powders.  Seaweeds  are  everywhere  used  by 
farmers  on  the  coasts  as  fertilizers. 


XI 
COLLECTINa  AT  BAR    HARBOE 

THE  beautiful  coast  of  Maine  is  a  particularly  good  field  for 
shore-collecting.  The  rocky  coast  harbors  the  boreal  fauna 
and  flora  which  depend  upon  such  physical  conditions,  and  the 
shores  at  Bar  Harbor  are  typical  of  those  found  elsewhere  in 
northern  New  England.  The  rocks  give  shelter  from  the  beating 
surf,  while  life  has  exposure  to  the  cold,  pure  waters  of  the  arctic 
current.  Everywhere  along  the  shore,  rock  pools  are  to  be  found. 
These  are  perhaps  the  most  fascinating  of  all  spots  to  the  col- 
lector. They  are  veritable  gardens  of  the  sea,  where  species 
flourish  which  naturally  belong  to  deeper  water,  but  which  find 
in  such  pools  conditions  suitable  to  their  existence. 

At  Bar  Harbor  one  well-known  and  frequently  visited  rock 
pool  is  found  in  Anemone  Cave.  Entering  a  field  at  Schooner 
Head,  one  turns  to  the  right  and  follows  the  rocky  shore  for  two 
or  three  hundred  feet.  It  is  diflicult  to  take  this  short  walk 
without  being  constantly  diverted  and  delayed  by  the  various 
attractions  one  meets,  such  as  the  tide-pools,  the  barnacles  which 
*in  places  whiten  the  rocks,  the  periwinkles,  the  purpura  shells, 
and  the  curious  algae ;  but  at  last  one  arrives  at  a  cavern  under 
an  overhanging  rock.  Here  is  a  large  tide-pool  which  at  first 
sight  displays  only  a  beautiful  scheme  of  color.  It  is  carpeted 
with  a  bright-pink  alga,.  Hildenbrandtia  rosea,  which  incrusts  the 
basin  of  the  pool. 

Interspersed  with  the  pink  are  patches  of  a  deep-red  color, 
having  a  velvety  appearance,  which  are  formed  by  another  crus- 
taceous  alga,  Fetrocelis  cnienta.     The  water  of  the  pool  is  of  crys- 

40 


COLLECTING  AT  BAR  HARBOR  41 

tal  clearness,  and  as  one  gazes  into  it  one  object  after  another 
comes  into  view,  until  one  is  filled  with  astonishment  at  the  num- 
ber of  beautiful  objects  the  pool  contains.  The  little  green  balls, 
one  half  of  an  inch  to  one  inch  in  diameter,  which  look  like  small 
green  tomatoes  scattered  on  the  stones,  are  Leathesia  difformis,  an 
alga  which  cannot  be  mistaken  for  any  other.  Bunches  of  Corallina 
officinalis^  which  resembles  coral,  as  the  name  indicates,  are  abun- 
dant. This  alga  should  be  examined  with  a  magnifying-glass. 
It  is  covered  with  calcareous  matter,  and  its  peculiar  form  of 
growth  is  beautiful  and  interesting. 

The  fronds  of  the  laminarian  Alaria  escidenta  are  tiny  here, 
while  just  outside  the  cave  they  are  to  be  seen  several  feet  in 
length,  beating  against  the  rocks  in  the  swash  of  the  waves. 
Thorny  sea-urchins  {Strongylocentrohis  drobachiensis)  make  green 
spots  which  look  like  tufts  of  moss.  YeUow  and  green  sponges 
in  little  cones  are  spread  over  small  surfaces.  Starfishes  and 
ophiurans  are  plentiful.  The  Purpiim  lapiUus  and  Littoriyia  litorea 
and  rudis  (periwinkles),  so  plentiful  on  this  coast,  are  present. 
The  Mytillus  and  the  Saxicava  and  the  Actncea  testudinaUs  are  also 
to  be  found.  A  green  crab  {Carcinus  mcenas)  is  snugly  hidden  in 
a  dark  nook  on  the  shady  side  of  the  pool,  and  many  small  crus- 
taceans scuttle  away  from  under  stones  as  they  are  lifted.  The 
collector  is  always  anxious  for  uncommon,  or  rather  less  plenti- 
ful, species,  and  here  are  found  two  specimens  of  nudibranchs, 
or  naked  mollusks,  JEolis  and  Dendronotus.  The  Chiton  ruher,  a 
jointed  mollusk,  was  also  found  here,  and  five  species  of  sea- 
anemones  were  counted.  As  this  is  a  favorite  hunting-ground, 
the  anemones  have  not  been  left  to  attain  full  growth;  but  there 
are  very  many  small  ones  which  at  first  are  not  distinguishable,  as 
they  retract  their  tentacles  at  the  slightest  disturbance  of  the  water 
and  are  then  quite  inconspicuous.  After  a  little  time  of  quiet 
watching  they  will  be  seen  putting  out  their  tentacles  and  expand- 
ing their  beautiful  flower-like  forms.  It  is  useless  to  try  to  cap- 
ture them  uninjured,  so  tightly  do  they  adhere  to  the  rocks,  and 
the  difficulty  of  preserving  them  in  an  expanded  form  is  so  great 
that  amateur  collectors  had  better  leave  them  undisturbed  to 
beautify  the  pool. 


42  INTRODUCTION 

It  was  hard  to  resist  robbing  this  rock  pool,  where  the  author 
in  half  an  hour  counted  twenty  different  species,  and  finally  left, 
feeling  that  its  treasures  were  not  half  discovered ;  but  collecting 
should  be  done  elsewhere,  and  this  pool  be  guarded  as  a  gem  to 
be  admired  and  not  to  be  despoiled. 

This  pool  in  Anemone  Cave,  although  so  very  attractive,  is 
surpassed  in  beauty  and  interest  by  pools  on  Porcupine  Island, 
at  the  base  of  the  cliff.  This  place  is  somewhat  difficult  of  access, 
and  the  timid  wiU  not  undertake  the  descent  to  it ;  but  the  en- 
thusiastic collector,  who  overlooks  small  obstacles,  will  be  repaid 
by  a  visit  to  this  spot,  where  all  the  treasures  of  Anemone  Cave 
are  multiplied  many  times  over.  These  pools  are  resplendent  with 
large  anemones,  hydroids,  nudibranchs,  mollusks,  echinoderms, 
crustaceans,  and  algae.  Alaria  esculenta,  several  feet  in  length, 
is  beaten  to  a  fringe  against  the  rocks,  and  Agarum  Tnrneri,  the 
sea-colander,  is  also  found  here,  together  with  beautiful  speci- 
mens of  Bhodymenia  palmata,  which  is  so  plentiful  that  it  reddens 
the  rocks. 

A  Metridium  marginatum,  the  most  common  sea-anemone  of 
this  coast,  was  taken  here  which  measured  six  inches  in  diameter. 
This  creature  threw  out  so  many  of  the  processes  used  for  de- 
fense that  it  seemed  at  first  as  though  it  were  covered  with  some 
seaweed ;  but  the  worm-like  movements  of  these  threads,  which 
measured  six  inches  or  more  in  length,  soon  disclosed  their  nature. 

On  the  more  accessible  shores  of  Porcupine  Island  are  found 
the  naked  mollusks  (nudibranchs)  ^olis  and  Bendronotus.  Cling- 
ing sideways  to  the  rocks  just  above  high- water  mark  are  many 
shells  of  LiUorina  rudis.  They  are  fastened  to  the  rocks  by  a 
glutinous  deposit  along  the  outer  lip,  and  the  peculiar  exposure 
of  the  open  end,  as  well  as  the  position  above  tide-mark,  indi- 
cates that  this  animal  is  undergoing  transformation  into  a  land 
species.  lAttorina  paUiata  is  abundant  on  the  rockweeds  (Fuciis) ; 
some  of  the  specimens  are  banded  with  yellow,  and  all  closely 
simulate  the  seaweed  on  which  they  cling.  Beautifully  banded 
specimens  of  lAttorina  litorea  are  also  plentiful.  Among  other 
shells  which  are  abundant  here  as  well  as  elsewhere  on  this  coast 
are  Purpura  lapillus,  Acmcm  testudinaUs,  Buccinum  undatum,  Mya 
arenaria,  and  MytiUus  edulis. 


COLLECTING  AT   BAR  HARBOR  43 

Under  the  rockweeds  in  small  pools  and  crevices  are  the  poly- 
zoans  Bugula  turrita  and  Menibrayiipora  pilosa,  and  the  hydroids 
Sertidaria  pumila  and  S.  argeutea. 

The  seaweeds  EJiodymenia  pahyiata  (dnlse)  and  Desmarestia  are 
plentiful ;  also  beautiful  worms,  crustaceans,  and  starfishes. 

A  very  interesting  beach  is  found  a  few  hundred  feet  south  of 
Otter  Cliffs,  to  which  an  easy  descent  is  made  if  one  follows  a 
pathway  leading  to  it  through  a  grove  adjacent  to  the  drive. 
Here  one  will  be  interested  in  the  study  of  numerous  and  beauti- 
ful rock  pools. 

Sea-urchins  (Strongylocentrotus  drohacJiiensis)  seem  to  carpet 
some  of  them,  having  the  appearance  of  moss}^  tufts.  Beautiful 
pink  and  purple  starfishes  (Asterias  vulgaris) ,  brittle-stars  {Ophio- 
pliolis  aculeata),  sea-cucumbers  {Pentada  fronclosa),  sea-anemones, 
aud  crabs  are  abundant.  If  one  lifts  a  stone  the  little  crusta- 
ceans Orchestia  and  Gammartis  will  hurry  away,  and  very  likely 
an  interesting  worm  or  a  nudibranch  will  be  found.  It  is  also 
most  interesting  to  watch  the  barnacles,  which  are  below  the 
surface,  reaching  out  their  curled,  feather-like  feet  in  regular 
rhythmic  grasping  motions.  The  common  mussels  {Mijtillus  edu- 
lis),  which  in  places  blacken  the  shore,  are  beautiful  under 
examination,  and  the  silky  network  or  byssus  which  forms  the 
anchorage  should  be  observed. 

The  rocks  are  hung  so  plentifully  with  Ascophyllum  nodosum 
(rockweed)  that  its  beauty  is  likely  to  be  passed  over  unnoticed. 
On  the  Ascophyllum  is  growing  in  tufts  Folysiphonia  fastigiata  ; 
other  seaweeds,  Rhodymenia  palmata^  CJiordaria  flagelliformis,  Des- 
marestia aculeata,  Corallina  officinalis,  and  Ceramium,  are  so 
abundant  that  one  forgets  to  value  them  at  the  moment.  Higher 
up  on  the  beach  the  rocks  are  spotted  with  papery  sheets,  which, 
floated  out  in  water,  prove  to  be  the  beautiful  purple  Porphyra.  A 
fine,  dark  colored,  hairy  scum  on  the  rocks  is  Bangiafusco-purpjurea. 
Sometimes  one  finds  here  fronds  of  Laminaria  which  have  been 
washed  ashore.  Various  green  algae  are  abundant.  Even  if  not 
collecting,  it  is  well  to  carry  a  small  tin  pail  to  the  beach  and 
float  out  pieces  of  the  algae  in  order  to  observe  carefully,  if  but 
for  a  moment,  the  beautiful  forms  they  have  in  their  natural  state. 
Watched  for  a  few  minutes  in  a  pail  of  water  they  disclose  curi- 


44  INTRODUCTION 

ous  and  surprising  forms  and  habits  which  are  difficult  to  watch 
leaning  over  a  pool. 

Most  of  the  various  species  mentioned  above  are  common 
along  the  whole  shore,  and  may  be  looked  for  at  almost  any 
point  where  the  water  is  free  from  contamination. 

At  the  sand-beach  are  found  species  which  do  not  inhabit  the 
rocky  shore,  as  the  sand-doUar  {Uchmarachnius  panria),  Polynices 
(Lunatia)  heros,  Mya  arenaria,  and  others.  After  a  storm  various 
deep-water  forms  are  washed  upon  this  beach.  Laminaria  digitata, 
six  feet  long,  is  found  here  sometimes  under  these  circumstances. 
(Jhordaria  flageUiformis,  resembling  long  switches  of  hair,  floats 
from  the  rocks  near  the  shore.  To  the  left,  on  the  rock  under 
the  overhanging  ledge,  is  a  tide-pool  which  one  would  hesitate 
to  deface  by  touching  a  single  specimen.  So  crystal-clear  is 
the  water,  so  brilliant  the  Sildenbrandtia,  so  lovely  the  CoraUma, 
that  all  seem  placed  there  to  excite  admiration. 

But  most  of  all  one  should  obtain  the  permission  of  the  owner 
to  visit  Rodicks  Weir.  Here  is  an  immense  natural  aquarium, 
full  of  living  wonders.  On  a  clear  day,  sunlight  penetrates  to 
the  bottom,  and  at  low  tide  the  whole  contents  of  the  weir  are 
clearly  seen  as  one  floats  through  the  inclosed  water-spaces. 
On  the  bottom  are  sea-urchins,  many  of  them  with  sticks  or 
stones  on  their  backs,  which  the  animals  have  placed  there  in 
the  endeavor  to  conceal  themselves ;  starfishes  feeding ;  and 
great  numbers  of  whelks  (Buccmum  undatimi).  Cuttlefishes  dart 
rapidly  about,  and  skates,  sculpins,  and  other  fishes  display  their 
curious  forms.  Very  likely  a  giant  jellyfish  (Cyania  arctica)  is 
entangled  in  the  brush,  so  that  one  can  examine  at  short  range 
its  wonderful  and  beautiful  parts.  Other  jellyfishes  may  be 
closely  scrutinized. 

The  alga  Folysiphonia  violacea  floats  in  long  feathery  tufts 
from  the  stakes. 

On  the  eel-grass  are  to  be  found  Lacuna  vincta  and  the  delicate 
iridescent  little  shells  of  Margarita  helicina. 

Every  tide  brings  different  species  of  the  ocean  fauna  to  tem- 
porary imprisonment  in  this  inclosure,  so  that  it  is  difficult  to 
say  what  one  may  not  chance  to  find  in  this  interesting  place. 


Part  I 
MARINE  ALG^ 


SEAWEED 

When  descends  on  the  Atlantic 

The  gigantic 
Storm- wind  of  the  eqninox, 
Landward  in  his  wrath  he  scourges 

The  toihng  surges, 
Laden  with  seaweed  from  the  rocks ; 

From  Bermuda's  reefs;  from  edges 

Of  sunken  ledges 
In  some  far-off,  bright  Azorej 
From  Bahama  and  the  dashing, 

Silver-flashing 
Surges  of  San  Salvador; 

Ever  drifting,  drifting,  drifting 

On  the  shifting 
Currents  of  the  restless  main; 
Till  in  sheltered  coves,  and  reaches 

Of  sandy  beaches. 
All  have  found  repose  again. 

Longfellow. 


BLUE-GREEN  SEAWEEDS 
(CYANOPHYCE^) 

GRASS-GREEN  SEAWEEDS 
(CHLOROPHYCE^) 


47 


TABLE  SHOWING  THE  CLASSIFICATION   OF  THE  BLUE-GREEN 
SEAWEEDS  DESCRIBED  IN   THIS  CHAPTER 

Class 


Order 


NOSTOCACE^ 


Subclass 

Cyanophyceae 

(Blue-Green  Seaweeds) 

Genera 
/  Spirulina 
)  Oscillaria 
Calothrix 


\ 


Lyngbya 


Species 


j  L»  maJMScula 
t  L.  ferruginea 


48 


BLUE-GEEEN    SEAWEEDS 

THE  minute  algse,  whicli  form  patches  of  purple  color  on 
rocks,  slimy  layers  or  spots  on  wharves,  bluish-green  slime 
on  mud,  emerald-green  films  on  decaying  algge,  blue-green 
slime  on  brackish  ditches,  and  so  on,  are  various  species  of  the 
subclass  Cyanophyceae.  The  prevailing  color  of  these  plants  is 
blue-green,  but  some  are  purple,  brown,  or  pink.  Some  of  them 
are  gelatinous  in  texture  and  shapeless,  others  have  more  definite 
forms ;  but  all  are  too  small  to  classify  without  the  aid  of  a  power- 
ful glass,  and  are  not  of  special  interest  except  to  the  botanist. 

GrENERA  OscUlarla  and  Spirulina 

The  genus  Oscillaria  is  so  named  from  an  oscillating  move- 
ment which  these  filamentous  plants  show  when  viewed  under 
the  microscope.  They  are  very  delicate  blue-green  threads  occur- 
ring singly,  or  in  loose  or  felt-like  floating  masses,  or  like  slime 
or  scum,  on  mud  or  woodwork.  In  Spirulina  the  filaments  are 
spirally  twisted  like  a  corkscrew  and  also  have  a  vibrating  move- 
ment. Spirulina  is  often  found  growing  with  Oscillaria ^  and 
forms  purple  patches  on  wharves. 

Genus  Calothrioc 

C"  Beautiful  hair^') 

Filaments  one  tenth  of  an  inch  long,  terminating  in  transparent 
hair-like  points,  occasionally  branching.  The  plant  grows  in  fine 
tufts  or  like  a  fringe  on  algae  or  in  patches  on  rocks.  Sometimes 
it  forms  a  spongy  layer,  again  a  velvety  stratum.  The  color 
varies  in  different  species;    it  may  be  bright  green,  brownish- 

4  49 


50  MARINE  ALG^ 

green^  or  dark  bluisL -purple.     The  genus  is  very  common,  and 
the  plants  are  often  found  on  the  bottoms  of  boats. 

Genus  Lynghya 

(Named  for  Hans  Christian  Lynghye,  a  Banish  botanist) 


L,  rnajuscula,  mermaid's-bair.  The  filaments  are  curled  or  crisped, 
long-,  thick,  and  tenacious,  matted  together  at  the  base,  and  blackish- 
green.  The  species  grows  in  tufts  on  eel-grass  and  algae,  and  is  often 
found  floating  free.  It  is  common  in  summer  everywhere  south  of  Cape 
Cod  and  on  the  Pacific  coast. 

L,  ferruginea  or  cestuarii.  In  this  species  the  filaments  are  thin, 
soft,  and  without  stabihty  (flaccid),  so  that  they  lie  flat  like  a  thin 
stratum.  They  are  verdigris-green  in  color,  and  are  found  in  brackish 
pools  and  ditches  and  on  muddy  shores  near  the  sea. 


TABLE   SHOWING  THE  CLASSIFICATION  OF   THE  GRASS-GREEN 
SEAWEEDS  DESCRIBED  IN  THIS  CHAPTER 

Class 

ALG^ 

Subclass 
Ghlorophycese 

(Grass- Green  Seaweeds) 
Genera 
Ulothrix 

Chcetomorpha 


Orders 


CONPERVACILS: 


ULVACEE 


Cladophora 
Ulva 

Enteromorpha 


VALONIACKS: 


^Monostrofna 

Group  Siphoneae 
J  Chamcedoris 
\  Anadyomene 

{Acetahiilaria 
Dasycladus 
Cymopolia 

Penidllus 

UDOTEACEJE    (  Udotea 


Halimeda 
CODIACKE     {f^VOP^^ 


. 


CATILERPACE^    <  Caulerpa 


Species 

C,  fnelagoniuin 
C  cerea 
C  linum 
C  arcta 
C,  rupestris 
C.  gracilis 
JJ,  lactuca 
U,  latissima 
E.  ctathrata 
E,  compressa 
E.  intestinalis 
.E,  lanceolata 


C,  annulata 
A .  flahellata 

A,  crenulata 

D,  occidentalis 
C.  barbata 

JP.  dumentosus 
JP,  capitatus 
P.  Phcenioc 
JJ,  flahellata 
U.  eonglutinata 
H.  tuna 
H,  tridens 
.  H.  opuntia 

B,  plujnosa 

C,  tomentosum 
C  prolifera 

C.  Mexicana 

C,  pliiinosa 

.C.  Wurdemanii 


51 


GEASS-OREEN  SEAWEEDS 

THERE  can  hardly  be  a  more  fascinating  group  of  plants 
than  this,  whether  to  the  strictly  scientific  botanist  or  to 
the  more  catholic  lover  of  nature.  The  green  algae  are  among 
the  most  widely  diffused  of  plant  forms.  They  grow  practically 
in  every  place  where  enough  moisture,  together  with  light  and 
air,  is  to  be  had.  Between  tide-marks  on  almost  every  coast, 
floating  on  the  surface  of  the  deep  sea,  covering  damp  earth, 
walls,  palings,  and  tree-trunks,  sticking  to  the  surface  of  leaves 
in  the  moist  atmosphere  of  tropical  forests  and  jungles,  and  in- 
habiting almost  every  river,  brook,  pond,  ditch,  or  casual  pool  of 
rain-water  in  all  quarters  of  the  globe,  are  members  of  this 
ubiquitous  group  to  be  found."  ^ 

The  grass-green  seaweeds  are  more  simple  in  structure,  and 
therefore  are  lower  in  order,  than  the  red  or  brown  algae.  They 
are  among  the  lowest  of  all  plants,  many  of  them  being  minute 
single  cells.  They  abound  in  fresh  as  well  as  in  salt  water,  and 
in  this  respect  differ  from  the  other  groups,  the  red  and  the  brown 
alg^  being  almost  exclusively  marine  plants. 

As  one  approaches  the  shore,  the  attention  is  often  attracted 
by  the  green  mantle  w^hich  covers  everything  overflowed  by  the 
tides.  This  consists  largely  of  the  confervoid  alg«,  which  are 
very  abundant  and  are  found  almost  everywhere.  They  are 
dense  tufts  of  fine  thread-like  plants,  often  matted  at  the  base ; 
sometimes  they  are  sponge-like,  floating  masses. 

The  Ulvacese,  the  plants  next  higher  in  order,  are  the  first 
which  assume  ribbon-  and  leaf -like  expansions,  and  usually  first 
engage  the  attention  of  the  collector. 

1  Kerner. 
52 


GRASS-GREEN   SEAWEEDS  53 

In  the  green  algee  are  found  the  extreme  forms  of  one-celled 
plants.  In  JPleurococcus  the  cell  is  microscopic  in  size.  In  the 
Siphoneae  the  plant  still  consists  of  a  single  cell,  but  it  attains 
large  dimensions  and  develops  into  forms  resembling,  in  outward 
appearance,  leaf,  stem,  and  root  (see  CcmUrpa). 

Other  plants  consist  of  single  rows  of  cells,  called  filaments 
(Confervaceae),  or  of  cells  arranged  in  layers  or  flat  surfaces,  called 
membranes  (TJlvaceae). 

ORDER  CONFERVACE^ 

The  silkweeds.  This  order  is  characterized  by  cylindrical  cells 
strung  end  to  end,  forming  threads  or  filaments,  branched  and 
unbranched.  The  plants  inhabit  both  fresh  and  salt  water,  and 
are  very  abundant  and  widely  distributed.  They  grow  in  dense 
tufts,  often  matted  at  the  base. 

Genus  Ulothrix 

A  yellow-green,  unbranched,  decumbent,  soft,  hair-like  fleece 
on  the  surface  of  rocks,  extending  indefinitely.  This  genus  dif- 
fers from  Climtomorpha  in  the  character  of  its  filaments,  which 
are  soft  and  gelatinous  in  ZJlothrioo,  but  bristle-like  and  wiry  in 
Chcetomotpha. 

Genus  Chcetomorpha 

The  frond  is  filiform;  the  filaments  are  coarse,  rigid,  and 
unbranched.  In  some  species  the  filaments  grow  straight  and  in 
tufts  from  a  definite  base ;  in  others  they  are  twisted  together 
and  are  prostrate.  Often  they  are  found  floating  in  masses.  In 
C  tortuosa  the  filaments  are  as  fine  as  human  hair,  but  rigid,  and 
so  closely  interwoven  as  to  resemble  a  layer  of  wool  on  the  rocks. 
The  cell-divisions  give  a  striped  appearance  to  the  filaments  when 
dry. 

C  melagonium.  This  species  is  dark  green,  with  filaments  erect, 
coarse  as  a  double  bristle,  and  wiry ;  five  to  twelve  inches  lona^.  It  is 
found  in  rock  pools  from  Boston  northward.  It  does  not  adhere  to 
paper  in  drying,  and  loses  its  color  if  immersed  in  fresh  water.     (Plate 

III-) 

C.  mrea.    Yellowish-green,  with  filaments  erect  and  less  rigid  than 


54  MARINE  ALG^ 

in  C.  melagonium,  which  it  otherwise  resembles ;  tufts  three  to  twelve 
inches  long ;  cell- divisions  very  marked.  This  species  is  found  in  rock 
pools  from  Cape  Cod  to  New  York  Bay. 

C,  linum.  Bright  green;  filaments  coarse,  rigid,  twisted  together, 
and  prostrate.  It  is  found  floating  in  masses  and  forming  strata  on 
rocks  and  gravel  from  New  York  northward.  It  is  thought  by  some 
that  this,  as  well  as  C  picqiiotiana,  which  it  closely  resembles,  is  not 
a  true  species,  but  consists  of  the  mature  plants  of  the  species  C.  mela- 
gonium and  C.  (erea,  which  have  become  detached  from  their  holdfasts 
and  have  continued  to  grow.     (Plate  III.) 

Genus  Cladophora 

C'Branch-bearing'') 

Frond  filiform,  branched.  There  are  many  species  of  Cla- 
dophora, v^hich  differ  from  one  another  in  their  branching,  color, 
and  size.  They  abound  on  rocks  at  low-water  mark,  in  tide- 
pools,  in  muddy  ditches,  and  on  wharves.  They  are  especially 
characterized  by  being  so  profusely  branched  as  to  form  tufts  or 
spherical  masses,  by  which  the  collector  can  easily  distinguish  the 
genus. 

C  arcta.  Bright,  glossy  green ;  filaments  fine,  erect,  much  branched, 
two  to  eight  inches  long ;  tufts  dense,  more  or  less  entangled,  and  in 
bunches,  giving  a  starry  effect.  The  species  is  common  on  rocks  near 
low- water  mark  from  New  York  northward.  The  plants  vary  slightly 
in  appearance  with  the  season.     (Plate  III.) 

O.  rupestris.  Dark  green ;  filaments  straight,  rigid,  tufted ;  branches 
crowded  -,  many  branchlets  flattened  against  the  filaments,  so  that  the 
alga  somewhat  resembles  grass  j  five  to  ten  inches  long.  The  cell- 
divisions  show  plainly.  Plants  of  this  species  do  not  adhere  to  paper 
in  drying.  They  are  found  on  rocks  at  low-water  mark,  and  are  com- 
mon on  the  northern  New  England  coast.     (Plate  III.) 

C,  gracilis.  Bright  yellow-green ;  filaments  very  fine,  loosely  tufted, 
three  to  twelve  inches  long,  soft,  silky,  much  branched ;  branches  rather 
short,  and  branchlets  more  or  less  curved  and  aiTanged  in  a  comb-like 
manner.  It  grows  on  wharves,  in  muddy  pools,  and  on  eel-grass. 
(Plate  IV.) 

ORDER  XJLVACE^ 

The  plants  of  this  order  are,  with  few  exceptions,  formed  of 
celled  surfaces  and  show  the  earliest  type  of  an  expanded  leaf. 
The  cells  form  thin  membranes,  which  sometimes  are  broad  sur- 
faces of  no  definite  shape,  sometimes  are  narrow  and  ribbon-like, 
or  they  may  be  simple  or  branched  tubes.    When  the  membrane 


r  ./ 


"X 


^^^^^^^f-^My^^ 


PLATE   III. 


Chsetomorpha  melagonium. 
Cladophora  arcta. 


Chsetomorpha  linum. 
Cladophora  rupestris. 


PLATE  IV. 


Cladophora  gracilis. 
Ulva  lactuca,  var.  rigida. 


Ulva  lanceolata. 
Enteromorpha  clathrata. 


GRASS-GREEN  SEAWEEDS  55 

consists  of  a  single  layer  of  cells  it  is  Monostro^na  ("one 
layer")  J  when  it  consists  of  a  double  layer  it  is  Viva;  when  the 
layers  separate,  the  thallus  becomes  hollow,  and  it  is  then  En- 
teromorpha.  These  plants  are  mostly  a  brilliant  grass-green 
in  color,  are  silky  in  text  are,  and  are  attached  by  a  small  disk  to 
rocks  and  stones.  They  abound  everywhere,  and  are  commonly 
known  as  green  laver. 

Genus  Ulva 

Frond  a  thin,  silky,  flat  membrane,  sometimes  leaf -like,  again  an 
extended  surface  of  no  definite  shape.  These  are  the  largest 
green  algge.     They  are  common  everywhere. 

Z7.  lactuca,  the  sea-lettuce.  Frond  a  flat  membrane  of  various  shapes, 
sometimes  orbicular,  again  deeply  incised,  often  ribbon-like  j  margin 
always  much  waved  or  rufi&ed.  In  the  variety  rigida  the  frond  is  oval 
in  outline,  not  very  large,  and  quite  firm  or  rigid.  The  species  is  found 
on  rocks  exposed  to  the  action  of  the  waves.     (Plate  IV.) 

U,  latissima.  Frond  a  flat,  expanded  membrane  of  indefinite  shape, 
but  general  outhne  oval,  never  ribbon-like ;  attains  a  size  of  twelve  to 
twenty-fom'  inches  j  often  deeply  lobed,  very  waved,  often  perforated 
with  holes ;  membrane  brilliant  green,  thin,  smooth,  glossy.  It  grows 
apart  or  in  tufts,  and  is  found  everywhere,  in  all  stages  of  growth.  It 
is  the  largest  species  of  Ulva,  and  is  very  common  on  muddy  shores. 

Genus  Enteromorpha 

Fronds  tubular,  simple  or  branched,  sometimes  inflated.  The 
tubes  vary  in  size  in  different  species  and  also  in  the  same  spe- 
cies, some  being  fine  like  a  hair,  others  large,  and  flat  or  inflated. 
The  genus  is  widely  distributed  and  very  abundant.  Species  of 
Enteromorpha  grow  on  the  bottoms  of  ships,  and  in  nautical 
language  are  called  grass. 

E.  clathrata.  Fronds  thread-like,  tubular,  branched,  and  branches 
beset  with  numerous  fine  branchlets;  densely  tufted,  soft.  Common 
everywhere.     (Plate  IV.) 

E,  compressa.  Fronds  long,  slender,  branched,  tufted;  branches 
simple,  compressed,  extending  from  main  central  branch,  obtuse  at  ends, 
but  attenuated  at  base.  The  species  is  very  abundant  everywhere,  and 
is  a  useful  plant  for  the  aquarium.     (Plate  V.) 

E,  intestinalis.  Single,  long,  inflated  tubes  or  sacs,  obtuse  at  the 
apex,  very  attenuated  at  the  base  -,  fronds  often  crimped  and  twisted, 
resembling  an  intestine,  whence  the  name.    (Plate  V.) 


56  MAEINE  ALG^ 

IE,  lanceolata.  Formerly  called  Ulva  Linza.  Frond  narrow,  ribbon- 
like, six  to  twelve  inches  long,  one  inch  to  two  inches  wide ;  blunt  or 
pointed  at  apex,  tapering  at  base;  attached  by  a  disk;  edges  much 
ruffled;  bright  green,  soft,  thin. 

GrENus  Monostroma 

This  genus  resembles  Ulva,  but  is  more  delicate  since  it  has 
but  one  layer  of  cells,  as  its  name  implies.  The  frond  is  usually 
sac-like  at  first,  then  breaks  apart,  leaving  a  thin,  semi-trans- 
parent membrane  of  no  definite  shape. 


GROUP  SIPHONEiE 

The  distinct  and  peculiar  character  of  this  group  is  that  in  each 
individual  the  whole  plant  consists  of  but  one  cell.  There  are 
many  genera,  some  of  which  are  plants  of  elaborate  form  and 
considerable  size,  but  always  the  one  cell  expands  and  branches 
without  dividing  the  elongated  cavity  with  septa,  or  plates  of 
division.  In  Caulerpa  the  stability  of  the  plant  is  secured  by 
numerous  fibrils  which  emanate  from  the  interior  of  the  cell, 
forming  a  spongy  network  of  interlacing  filaments.  In  other 
orders  the  branches  gain  support  from  incrustation,  from  inter- 
lacing, and  from  cohering  on  the  edges. 

ORDER  VALONIACE^  "^ 

The  algae  of  this  order  are  found  only  in  tropical  or  subtropical 
waters.  Their  holdfasts  resemble  fibrous  roots  and  penetrate  the 
sand  or  coral  on  which  they  grow. 

Genus  Chamcedoris 

C.  annulata.  When  young  this  alga  consists  of  an  annulated  tube 
formed  of  a  single  cell.  The  annular  constrictions  occur  at  short  inter- 
vals, giving  it  the  appearance  of  being  jointed.  It  grows  to  the  height 
of  two  to  three  inches,  when  it  ceases  to  lengthen  and  produces  a  dense 
mass  of  filaments,  forming  a  head  or  spherical  tuft  one  inch  or  more  in 
diameter.  It  is  bright  grass-green  in  color,  rather  rigid  and  tough,  and 
when  mature  is  thinly  coated  with  carbonate  of  hme.  The  holdfast  is  a 
tuft  of  fibers.  The  species  is  found  at  Key  West  and  is  a  native  of  the 
West  Indies. 


PLATE  V. 


Enteromorpha  compressa. 
Enteromorpha  intestinalis. 


Enteromorpha  intestinalis. 
Anadyomene  flabellata. 


PLATE  VI. 


Acetabularia  crenulata. 
Penicillus  dumentosus. 


Dasycladus  occidentalis. 
Udotea  conglutinata. 


GRASS-GREEN  SEAWEEDS  57 


Genus  Anadyomene 

A.  fldbellata.  Frond  composed  entirely  of  brancaing  filaments, 
whicli  unite  and  form  an  undulating,  rigid  membranaceous  surface,  wMch 
seems  like  a  network  of  veins.  The  species  grows  in  bunches  on  short 
stems  in  the  fissures  of  tidal  rocks,  and  at  first  view  resembles  young 
Ulva.  It  is  a  very  curious  and  beautiful  alga,  and  should  be  examined 
with  a  glass.  It  is  one  inch  to  four  inches  in  diameter  when  fuU- 
growu.     (Plate  V.) 

ORDER  DASYCLADACE^ 

This  order  also  inhabits  only  tropical  or  subtropical  seas.  It 
is  placed  in  this  group,  although  only  the  main  axis  is  unicellu- 
lar. The  one-celled  axis  is  surmounted  or  encircled  by  whorls  of 
minute  filaments  or  branchlets  {ramiili),  which  protrude  through 
small  holes  and  are  either  persistent  or  deciduous.  In  the  latter 
case  the  fallen  filaments  leave  disk-like  scars  on  the  stem. 

Genus  Acetabiilaria 

A,  crenulata.  This  little  alga  resembles  a  mushroom  of  the 
Agaricus  variety  or  gilled  species,  and  so  is  easily  identified.  It  is  thinly 
incrusted  with  hme  and  is  found  on  rocks  and  coral,  within  tide-marks, 
on  the  Florida  reefs.  Wlien  full-grown  the  stipe  is  two  to  three  inches 
long  and  the  cap  one  half  of  an  inch  in  diameter.     (Plate  VI.) 

Genus  Dasycladus 

Fronds  destitute  of  calcareous  matter,  soft,  cylindrical  or  club- 
shapedj  single  unicellular  axis,  beset  with  fine  filaments  or 
ramuli. 

J),  occidentalis.  Frond  club-shaped,  one  to  two  inches  high,  one 
half  of  an  inch  or  less  in  diameter ;  covered  with  whorls  of  fine  filaments, 
making  the  fronds  almost  spongy ;  substance  soft  but  tough  ;  dark 
green.  These  plants  have  been  compared  to  foxes'  tails.  They  grow 
in  bunches  on  rocks  between  tide-marks.     (Plate  VI. ) 

Genus  Cymopolia 

C,  barhata.  Frond  branched,  dividing  regularly  in  pairs ',  thickly 
incrusted  with  lime.  Annular  constrictions  at  short  intervals  give  the 
branches  the  appearance  of  strings  of  beads.  Each  section  is  covered 
with  pores  or  scars  of  fallen  ramuli.  The  branches  terminate  in  tufts 
of  fine  filaments. 


58  MARINE  ALG^ 

ORDER  UDOTEACE^ 

Genus  Penicillus 
The  merman's  shaving-brush,  characteristic  of  coral  reefs. 

P,  dumentosus.  Holdfast  much  branched,  like  a  fibrous  root,  and 
penetrating  deep  into  the  coral  or  sand ;  stem  short,  thick,  more  or  less 
flattened,  sometimes  hollow,  covered  with  velvety  scurf;  top  covered 
with  loosely  spreading  tuft  of  soft  filaments  three  to  six  inches  long, 
which  branch  repeatedly  in  pairs  (dichotomous)  -,  color  deep  green. 
When  old,  these  plants  are  incrusted  with  a  thin,  porous  layer  of  car- 
bonate of  lime.     (Plate  VI.) 

jP.  capitatus.  Holdfast  a  dense  mass  of  fibers  two  or  more  inches 
long ',  stipe  one  to  five  inches  long,  one  fourth  to  one  third  of  an  inch  in 
diameter,  usually  cyhndrical,  sometimes  wider  at  top  than  at  base, 
sometimes  flattened ;  thickly  incrusted  with  lime,  which  is  smooth  and 
often  polished;  top  a  dense,  spherical  mass  of  filaments  one  to  two 
inches  in  diameter ;  filaments  branching  dichotomously,  and  rigid  from 
incrustation  of  lime. 

J*.  Fhoenix,  Stipe  cylindrical,  one  to  three  inches  long,  one  fourth  of 
an  inch  in  diameter,  thickly  incrusted  with  lime,  smooth ;  capitulum  or 
head  ovoid,  and  composed  of  filaments  which  are  incrusted  with  lime 
and  coherent,  forming  many  distinct,  flat,  wedge-shaped,  level- topped, 
spreading  laminae.     This  species  is  found  at  Key  West. 

Genus  Udotea 

U,  fldbellata.  Short,  flattened  stem,  expanding  into  a  broad,  fan- 
shaped,  smooth  frond,  concentrically  zoned;  margin  wavy;  thickly 
incrusted  with  hme.     Abundant  at  Key  West. 

JJ,  conglutinata.  Deeply  descending  root ;  stem  expanding  into  fan- 
shaped  frond ;  entire,  lobed,  or  irregularly  torn ;  shghtly  incrusted  with 
lime.  The  frond  is  composed  of  longitudinally  parallel,  adherent  flla- 
ments,  which  are  visible,  giving  a  striated,  rough  surface.     (Plate  VI.) 

Genus  Halimeda 

This  genus  resembles  the  corallines  externally,  and  is  abundant 
on  coral  reefs.  It  appears  as  if  formed  of  separate  parts,  resem- 
bling a  series  of  heart-  or  kidney-shaped  segments  strung  together. 
The  plants  are  more  or  less  incrusted  with  lime.  The  branching 
holdfast  grasps  particles  of  sand,  and  with  them  forms  a  solid 
ball. 

JET.  tuna.  Articulations  roundish  or  half  kidney-shaped,  one  half  to 
three  quarters  of  an  inch  broad ;  frond  flat,  smooth,  and  thinner  than 
most  species ;  bright  green ;  somewhat  flexible,     (Plate  VII.) 


V    r   « 


^i^ 


'd0 


PLATE  VII. 


Halimeda  tuna. 
Bryopsis  plumosa. 


Halimeda  tridens. 
Codium  tomentosum. 


>  'I"-; 


X 


f?' 


.y 


% 


\ 


Caulerpa  Mexicana. 
Caulerpa  plumaris. 


PLATE   VIII. 


Caulerpa  Wurdemanii. 
Caulerpa  paspalold.es. 


GRASS-GREEN  SEAWEEDS  59 

jff,  tridens.  Fronds  solitary,  erect  j  base  composed  of  confluent 
articulations ;  above  divided  into  numerous  branches  of  articulations, 
which  are  all  flat,  and  in  one  plane  giving  a  fan -shaped  outline  ;  middle 
joints  wedge-shaped;  upper  ones  divided  into  three  lobes,  frequently 
bearing  articulations  at  the  summit  of  each  lobe  -,  thinly  incrusted  with 
lime ;  color  bright  green.     (Plate  VII.) 

S.  opuntia.  Articulations  kidney-shaped,  flat,  rather  thin ;  margins 
scalloped;  irregularly  branched  and  spreading;  dense  tufts. 


ORDER  CODIACE^ 
Genus  Bryopsis 

('^  Moss-like'") 

There  are  said  to  be  about  twenty  species  of  this  genus.  They 
are  distinguished  by  the  manner  of  branching,  but  are  not  very 
definitely  marked.  All  are  erect,  one-celled,  branching  stalks, 
and  are  feather-like  in  appearance. 

S,  pliitnosa.  Fronds  branched  twice  or  more;  branchlets  or  pin- 
nules tapering  as  they  rise  on  the  stalk,  giving  a  triangular  outline ; 
stalk  naked  below ;  plants  a  vivid  dark  green  in  color,  two  to  six  inches 
long,  growing  in  tufts  on  wharves  and  stones  at  low-water  mark  and  in 
tide-pools.  It  is  common  along  the  whole  Atlantic  and  Pacific  coasts. 
It  is  well  to  use  salt  water  for  mounting  this  alga,  since  the  green  color- 
ing-matter or  granular  endochrome  with  which  it  is  filled  easily  escapes. 
(Plate  VII.) 

Genus  C odium 

C  tomentosum.  This  is  called  the  commonest  seaweed  in  the  world. 
It  is  abundant  in  every  latitude,  yet  it  does  not  appear  on  the  eastern 
coast  of  North  America.  It  is  found  on  the  gtdf  coast  of  Florida  and 
is  plentiful  on  the  Pacific  coast.  The  fronds  are  often  a  foot  long,  com- 
posed of  closely  packed,  club-shaped  branches  dividing  in  a  forking 
manner,  and  densely  covered  with  fine  filaments  which  give  them  a  soft, 
sponge-like  texture.     (Plate  VII.) 


ORDER  CAULERPACE^ 
Genus  Caulerpa 

CFrom  two  Greek  tvords  meaning  ''stem"  and  ''creep  "^ 

Caulerpa  is  the  only  genus  of  its  order,  but  it  contains  about 
a  hundred  species,  many  of  which  resemble  mosses,  ferns,  or  cacti. 
Each  plant  is  composed  of  a  single  cell,  however  much  it  may  be 


60  MARINE  ALG^ 

ramified.  The  frond  consists  of  a  prostrate  stem,  from  the  lower 
side  of  which  root-like  fibers  or  holdfasts  descend  into  the  hard 
sand  or  coral,  and  from  the  npper  side  leaf-  and  branch-like 
secondary  fronds  arise.  These  plants  grow  luxuriantly  in  tropi- 
cal waters,  extending  over  large  surfaces,  and  are  the  chief  food 
of  turtles.     (Plate  VIII.) 

C.  prolifera.  Frond  or  lamina  flat  and  leaf -like,  two  to  four  inches 
long,  one  half  to  three  quarters  of  an  inch  wide,  either  simple  or  once 
forked ;  margin  entire.  Similar  laminae  spring  from  the  surface  or  from 
the  edge  or  base  of  the  different  leaf-Uke  portions.  Laminae  rise  from 
the  upper  side  of  the  creeping,  rooting  stem.  Its  substance  is  somewhat 
horny  and  translucent. 

C.  MeorAcana,  Prostrate,  creeping  stem,  with  rootlets  or  holdfasts 
below,  and  leaf -like  fronds  above ',  fronds  simple  or  with  one  or  two 
branches  deeply  cut  in  narrow  lobes  nearly  to  the  center.  The  species 
abounds  at  Key  West.     (Plate  VIII.) 


II 

OLIVE-GREEN  AND  BROWN  SEAWEEDS 
(PH^OPHYCE^) 


TABLE    SHOWING    THE    CLASSIFICATION    OF  THE    OLIVE-GREEN 
AND  BROWN  SEAWEEDS  DESCRIBED  IN  THIS  CHAPTER 

Class 

AL6JB 

Subclass 
Phseophycese 

( Olive- Qreen  and  Brown  Seaweeds) 
Genera 


Orders 


ECTOCAEPACE^    J  Ectocarpus 


. 


SFHACELARIACE^ 


BALFSIACE^ 


ENC(ELIAC£^ 


DESMABESTIACE^ 


r  Sphacelaria 
\  Cladostephus 
JRalfsia 

iPunctaria 
Asperococcus 
Phyllitis 

J  Desmarestia 
\Arthrocladia 


Species 
E,  littoralis 
E.  siliculosus 
E,  viridis 
E,  tomentosus 
cirrhosa 
radicans 
C,  verticillatus 


(S. 


DICTYOSIPHONACE^        JMctyosiphon 


J*,  latifolia 
P.  tenuissima 
P.  plantaginea 
A.  echinatus 
J*,  fascia 
■  X).  viridis 
J),  aculeata 
.  D,  ligulata 
A*  villosa 

J),  fceniculaceus 


ELACHISTACE^ 


CHOBDARIACE^ 


Elachista 

{Chordaria 
Mesogloea 
Leathesia 
Myrionema 

62 


C.  flagelliformis 
(  M,  virescens 
\  M.  divaricata 


OLIVE-GREEN  AND  BROWN  SEAWEEDS 


63 


Orders  Genera 

Chorda 

Alaria 

Agarimi 

Lmninaria 


LAMINABIACE^ 


DICTYOTACE^ 


CUTLEBIACE^ 


Macrocystis 
Nereocystts 
JLessonia 
ThalassiophyUum 

Dictyota 

Zonaria 
Taonia 
Fadina 
Haliseris 

CuUeria 


Himanthalia 

Fucus 

FXTCACEJE     ( Ascophyllum 
I  Phyllospora 
Cystoseira 
Halidrys 

Sargassum 


Species 

C,  filum 
A,  esculenta 
A,  Turner i 
L,  longicruris 
L.  saccharina 
L,  digitata 


{ 


2>.  fasciola 

D.  dichotoma 

Z,  lobata 

T,  atomaria 

J*,  pavonia 

H,  polypodioides 

C,  multifida 

H.  lorea 
F.  vesiculosus 
F,  serratus 
F.  furcatus 
.F.  ceranoides 
A,  nodosum 
F.  Menziesii 
C.  expansa 
H,  osmunda 
S,  vulgar e 
S,  Montagnei 
S,  bacciferum 


OLIVE -GEEEN  AND  BROWN 
SEAWEEDS 

THIS  subclass  contains  some  of  the  most  remarkable  of  the 
seaweeds.  It  is  especially  notable  for  the  diversity  of  its  plant 
forms,  which  range  from  filaments  to  plants  which  appear  to  have 
stems  and  leaves  {Sargassum).  The  species  vary  in  size  from  very 
small  fronds  to  those  of  immense  size  (the  Zaminariacece).  It  in- 
cludes Fucus  (the  rockweeds),  a  very  conspicuous  genus,  which 
furnishes  fully  three  fourths  of  the  vegetable  covering  of  the 
tidal  rcfcks  in  the  localities  in  which  it  grows. 

ORDER  ECTOCARPACEJE 

This  order  comprises  many  species  of  branched,  filamentous 
plants,  some  of  which  are  of  hair-like  fineness  and  form  beautiful 
feathery  tufts  of  brownish  or  olive-green  color.  They  resemble, 
except  in  their  tawny  color,  the  green  alga  Cladopliora. 

The  name  is  derived  from  Greek  w^ords  meaning  "outside" 
and  "  fruit,"  the  spores  of  the  plants  being  borne  on  the  branches. 

The  species  are  determined  by  the  arrangement  of  the  spores, 
according  as  they  are  in  the  pod-like  branches,  in  groups,  or  in 
cases  on  stalks.  Since  these  differences  are  not  perceptible  to 
the  naked  eye,  it  is  impracticable  to  describe  many  species,  or  for 
the  amateur  collector  to  try  to  separate  them. 

Genus  XJctocarj^us 

E.  littoralis.  Filaments  fine,  in  dense  tufts,  interwoven,  six  to  twelve 
inches  long ;  pod  linear  in  the  substance  of  the  branches  -,  color  olive- 
green.  This  is  the  most  common  species  of  Ectocarpus^  and  grows  abun- 
dantly everywhere,  appearing  like  large,  fine,  dull-green  plumes.   ( Plate  IX. ) 

64 


OLIVE-GREEN   AND   BROWN  SEAWEEDS  65 

E,  siliciilosus.  Tufts  loosely  entangled  at  the  base,  free  and  feathery 
above,  of  indefinite  length;  spores  in  pod-like  forms  at  the  ends  of  the 
branches.     Common  on  the  larger  algae  and  on  wharves. 

E,  viridis.  Tufts  a  little  more  loose  and  expanding  than  in  E.  silicu- 
losus;  spores  in  pods  at  the  base  of  the  branches.     (Plate  IX.) 

E,  tomentosus.  Fine  filaments,  densely  interwoven  into  rope-like, 
spongy  masses,  two  to  four  inches  long ;  yellowish-brown  j  pods  on  stalks. 
Found  in  summer  growing  on  Fucus. 


ORDER  SPHACELARIACEiE 

Genus  Sphacelaria 

S,  cirrhosa,  Olive-brown ;  branched,  feathery  filaments,  one  half  of 
an  inch  to  two  inches  long.  Each  branch  ends  with  an  oblong,  swollen  cell 
containing  a  dark  gTanular  mass  which  gives  it  a  withered  appearance. 
These  cells  can  be  seen  with  a  strong  pocket-lens.  It  forms  dense,  globe- 
like tufts  on  Fucus. 

S,  radicans.  Filaments  one  half  of  an  inch  to  one  inch  high;  branches 
few  and  hairy.  It  forms  a  dense,  grass-like  covering,  of  indefinite  extent, 
on  the  under  side  of  muddy  rocks.     Found  on  the  New  England  coast. 

Genus  Cladostej^hus 

C,  vertieillatus.  Fronds  bristle-like,  dividing  regularly;  covered 
with  whorls  of  branchlets  set  close  to  the  stems,  each  whorl  overlapping 
the  previous  one,  giving  the  plant  a  spongy  appearance.     (Plate  IX.) 


ORDER    RALFSIACEiE 

Genus  Mcilfsia 

The  species  of  this  genus  are  brown,  leathery,  crustaceons 
expansions  of  indefinite  form,  one  inch  to  six  inches  in  diameter, 
resembling  lichens.  They  appear  on  rocks  in  shallow,  exposed 
pools. 

ORDER   ENCCELIACE-ffi 

Genus  JPunctaria 

Dott6d-weeds.  Fronds  pale  olive-green,  membranaceous,  leaf- 
like, with  short  stem ;  covered  with  spores  which  appear  like  dots. 

JP.  latifolia.  Frond  pale  green,  four  to  twelve  inches  long,  one  inch  to 
five  iaches  wide,  leaf-hke,  and  tapering  suddenly  to  a  short  stalk;  much 

5 


66  MARINE  ALG^ 

waved  on  margin j  substance  soft  and  thin;  dotted  with  spores.  In  the 
young"  plants  fine  hairs  emerge  from  the  dots,  but  disappear  later,  and 
the  fronds  become  darker  and  more  rigid.  Found  in  summer  on  rocks 
and  on  other  algae  on  the  Long  Island  and  New  England  coasts. 

P,  temiissima*  Fronds  smaller  and  more  slender  than  in  P.  latifolia; 
thin  and  delicate.     Found  on  eel-grass  and  Chorda  filum. 

J*,  plantaginea.  Fronds  dark  brown,  leathery,  leaf-hke,  blunt  or 
wedge-shaped  on  top ;  dense  clusters  of  hairs  on  the  dots ;  six  to  twelve 
inches  long,  one  inch  to  one  and  a  half  inches  wide. 

Genus  Asj^erococcus 

This  genus  differs  from  Pimctaria  in  having  a  tubular  instead 
of  a  flat  frond.     (Plate  IX.) 

A .  echinatus.  Resembles  Enteromoiyha  in  being  tubular ;  compressed 
or  inflated  -,  obtuse  at  the  apex ;  attenuated  at  the  base.  It  differs  from 
Enteromorplia  in  being  ohve  in  color,  and  in  being  covered  with  small 
oblong  dots  of  darker  shade.  When  the  plant  is  young  the  dots  are 
hairy.  It  grows  in  clusters,  two  to  eighteen  inches  long,  one  half  of  an  inch 
to  one  inch  wide.     Common  along  the  New  England  coast. 

Genus  I^Tiyllitis 

P,  fascia.  Fronds  light  olive-green,  leaf-hke,  three  to  six  inches  long, 
one  fourth  to  one  half  of  an  inch  wide;  margin  entire,  slightly  waved; 
contracted  at  base  to  short  stalk ;  attached  by  disk.  This  species  grows 
in  bunches  on  rocks  and  stones  at  low- water  mark,  and  is  very  common 
everywhere.     (Plate  X.) 


ORDER  DESMARESTIACE-ffi 

(Named  for  M.  Desmarest,  a  French  naturalist) 

Genus  Desmarestia 

D.  viridis.  Filaments  cyhndrical,  about  as  thick  as  a  bristle ;  branches 
opposite,  in  pairs,  at  intervals  on  the  main  stem.  The  branches  branch 
again  and  continue  to  be  disposed  in  the  same  manner.  All  are  long  and 
ultimately  become  very  fine.  The  color  is  olive-green,  becoming  verdi- 
gris-green when  exposed  to  the  air  for  a  short  time  or  placed  in  fresh 
water.  The  species  grows  in  deep  tide-pools  and  below  low- water  mark, 
forming  fine,  feathery  plumes,  often  a  yard  long,  which  give  submerged 
rocks  the  appearance  of  a  luxuriant  garden.     (Plate  X.) 

2).  aculeata  ("spiny").  Fronds  cylindrical  at  base,  flattened  above; 
branches  long  and  straight,  arranged  alternately,  when  young  beset  with 
pencils  of  fine  hairs,  often  one  half  of  an  inch  long,  which,  later,  fall  off, 
leaving  alternate  spines  along  the  edges  of  the  flattened  branches.     It 


PLATE  IX. 


Ectocarpus  littoralis. 
Cladostephus  verticillatus. 


Ectocarpus  viridis. 
Asperococcus  bullosus. 


PLATE  X. 


Phyllitis  fascia. 
Desmarestia  aculeata. 


Desmarestia  viridis. 
Desmarestia  ligulata. 


OLIVE-GREEN  AND  BROWN  SEAWEEDS  67 

grows  from  one  foot  to  six  feet  in  length,  below  low-water  mark,  and  is 
found  washed  ashore.  It  is  an  attractive  plant  in  the  spring,  but  is  brown 
and  coarse  when  old.     Common  everywhere.     (Plate  X.) 

D,  ligulata.  Fronds  two  to  six  feet  long,  pinnate,  having  a  flat  main 
stem  one  half  of  an  inch  or  more  wide,  with  opposite  flat  branches;  leaf- 
lets arranged  along  the  edges  of  the  branches,  pointed  at  each  end,  and 
bordered  with  forward-pointing  spines.  It  is  found  washed  ashore,  in 
abundance,  in  California,  but  is  not  found  on  the  Atlantic  coast. 
(Plate  X.) 

Genus  Arthrocladia 

A,  villosa,  Ohve-brown  filaments,  resembling  fine,  knotted  threads, 
each  knob  having  a  whorl  of  dehcate  filaments.  It  grows  from  six  inches 
to  three  feet  long,  in  deep  water.  It  is  rare,  but  is  occasionally  found  on 
the  New  England  coast. 


ORDER  DICTYOSIPHONACE^ 

Genus  Dictyosiphon 

D,  fceniciilaceiis.  Fronds  filiform,  bristle-like,  branching  into  deli- 
cate, hair-like  branches ;  yellowish-brown.  It  resembles  Chordaria  flagel- 
Uformis,  but  is  much  finer.     (Plate  XI.) 

ORDER  ELACHISTACEiE 

Genus  JElachista 

The  plants  of  this  genus  are  small,  olive-colored,  unbranched, 
hair-like  filaments,  growing  in  dense,  radiating  tufts,  one  half  of 
an  inch  in  height,  on  Fucus.  They  are  interesting  to  the  micro- 
scopist,  but  not  to  the  collector. 

ORDER  CHORDAEIACEiE 

C' Cord-like") 

Genus  Chordaria 

C,  flagelliformis  ("whip-like").  Firm,  leathery,  somewhat  elastic, 
slimy  strings,  six  to  twenty-four  inches  long,  and  twice  as  thick  as  a 
bristle ;  branches  mostly  undivided,  short  or  long,  irregularly  placed  on 
the  main  axis,  and  curving  inward  at  the  top  of  the  frond )  main  axis 
not  extending  as  far  as  the  branches ;  blackish  in  color ;  attached  by  a 
disk  to  stones  and  shells ;  solitary  or  in  bunches.  It  is  common  along 
the  New  England  coast.     (Plate  XI.) 


68  MARINE  ALG^ 

Genus  Mesoglcea 

M,  virescens.  Soft,  slimy  filaments,  with  branches  and  branchlets ; 
olive-greeno     (Plate  XI.) 

M,  divaricata.  Fronds  two  to  twenty-four  inches  high ;  branching 
irregularly,  and  generally  without  definite  main  axis ;  branches  flexuous, 
solid  at  first,  later  hollow ;  branchlets  short  and  wide- spreading.  Com- 
mon from  Cape  Cod  southward:  abundant  in  Long  Island  Sound. 
(Plate  XI.) 

Genus  Leathesia 

This  singular  alga  resembles  a  tuber  and  cannot  be  mistaken 
for  any  other  plant.  Its  fronds  are  gelatinous,  fleshy  balls,  one 
half  of  an  inch  to  two  inches  in  diameter,  at  first  solid,  afterward 
lobed  and  hollow.  It  grows  singly  or  in  bunches  on  algae  and  on 
sand-covered  rocks,  and  is  found  in  summer  on  every  coast.  The 
common  species  is  known  as  L.  difformis  or  L.  tuderiformis. 

Genus  Myrionema 

Minute  algae  which  grow  on  other  plants  and  which  appear 
like  dark  spots,  or,  at  first,  like  stains,  on  Ulva,  Unteromorpha,  and 
small  red  alg^.  These  spots,  which  to  the  naked  eye  appear 
like  decaj,  show,  under  the  microscope,  a  jelly-like  substance 
full  of  beaded  filaments. 

ORDER  LAMINARIACE^ 

The  plants  of  this  order  have  large  and  coarse  fronds  (some 
attaining  an  immense  size),  with  stems,  branching  root-like  hold- 
fasts, and  expanded  leaf -like  laminae.  They  are  leather-like,  not 
articulated,  olive-green  or  brown  in  color,  and  sometimes  yellow 
and  semi-transparent.  They  grow  in  deep  water  and  are  found 
washed  ashore.  Sometimes  small  plants  are  found  in  deep  tide- 
pools  at  low- water  mark.  Some  species  are  perennial.  In  these 
instances  the  stems  only  survive,  and  the  laminae  are  repro- 
duced annually.  The  new  growth  takes  place  at  the  apex  of  the 
stem.  The  old  lamina  is  pushed  off,  but  is  held  on  the  summit 
of  the  new  growth  until  the  latter  has  matured. 

In  the  genus   Chorda  the  fronds  are  cylindrical  j  in  Agarum 


PLATE   XI. 


Dictyosiphon  foeniculaceus. 
Mesoglcea  virescens. 


Chordaria  flagelliformis. 
Mesogloea  divaricata. 


Chorda  filum. 
Agarum  Turneri. 


PLATE  XII. 


Alaria  esculenta. 
Lamiuaria  saccharina. 


OLIVE-GEEEN  AND  BROWN  SEAWEEDS  69 

the  laminae  are  perforated ;  in  Alaria  there  are  wing-like  leaflets 
below  the  laminge. 

The  Laminariacece  and  Fucacece  are  the  seaweeds  used  in  making 
kelp.  For  this  the  alg^e  are  burned,  and  the  ash  is  then  separated 
into  its  different  mineral  constituents  and  used  for  various  manu- 
facturing purposes. 

Genus  Chorda 

C,  fllum.  Entire  frond  cyhndrical,  divided  internally  by  transverse 
septa ;  one  fourth  to  one  half  of  an  inch  in  diameter,  tapering  at  each 
end ;  ordinarily  one  to  twelve  feet  long,  but  sometimes  attaining  a  length 
of  forty  feet.  When  young  the  frond  is  covered  with  fine,  transparent 
hairs ;  later  it  is  brown  and  leather-like.  The  growth  takes  place  at  the 
base,  just  above  the  disk-like  holdfast,  and  at  the  apex  it  is  constantly 
dying  off.  The  species  is  common  on  Northern  shores,  at  and  below  low- 
water  mark.  Often  it  is  in  masses  which  seem  like  meadows  of  waving 
grass  under  water.  Various  small  algae  and  many  zoophytes  are  to  be 
found  on  the  fronds.     (Plate  XII.) 

Genus  Alaria 

This  genus  is  readily  distinguishable  by  the  fact  that  it  has 
leaflets  below  the  lamina.     It  is  found  north  of  Cape  Cod. 

A.  esculenta.  Stem  compressed,  four  to  twelve  inches  long,  one 
fourth  to  one  half  of  an  inch  wide,  and  running  like  a  midrib  through 
the  lamina ;  lamina  one  to  ten  feet  long,  two  to  ten  inches  wide,  fre- 
quently torn  and  ragged ;  margin  wavy ;  leaflets  three  to  eight  inches 
long  and  without  midrib,  growing  on  both  sides  of  the  stem,  below  the 
lamina.  The  spores  are  produced  in  the  leaflets  in  the  autumn.  This  is 
an  edible  alga  and  is  used  as  food  in  Scotland  and  Ireland,  where  it  is 
called  henware,  badderlocks,  murhns,  and  so  on.     (Plate  XII.) 

Genus  Agarum 
The  sea-colanders. 

A.  Tiirneri.  Stem  two  to  twelve  inches  long,  round  below,  flattened 
above,  and  extending  like  a  midrib  through  the  lamina ;  lamina  one  foot 
to  four  feet  long,  with  holes  over  the  whole  surface  ;  margin  wavy.  The 
perforations  in  the  lamina  are  produced  by  conical  hollow  papillsB  which 
cover  the  young  frond  and  which  at  length  burst,  leaving  a  hole  which 
enlarges  as  the  plant  expands.  This  species  is  found  from  Cape  Cod  to 
Greenland. 

There  are  other  species,  which  differ  from  this  one  in  the  size  of  the 
perforations,  the  shape  of  the  lamina,  and  the  prominence  of  the  midrib. 
Harvey  describes  the  plant  as  an  arctic  genus  growing-  ten  to  twelve 
feet  long.     (Plate  XII.) 


70  MARINE  AhGM 


Genus  Laminaria 

The  plants  of  this  genus  are  all  large,  varying  from  one  foot  to 
twelve  feet  or  more  in  length.  They  are  of  wide  geographical 
range,  and  are  more  numerous  in  species  than  any  others  of  the 
order.  They  are  commonly  known  as  oarweeds,  tangle,  devil's- 
aprons,  sole-leather,  kelp,  sea-furbelows,  and  so  on. 

X.  longicruris  (*' long-stalked").  Stem  six  to  twelve  feet  long,  one 
to  two  inches  thick,  slender  and  solid  at  base,  hollow  and  inflated  at  the 
middle,  contracted  at  the  top  5  attached  by  a  strong,  branching,  root-like 
holdfast ;  color  light  brown.  The  large,  single,  leaf-hke  lamina,  usually 
shorter  than  the  stem,  is  five  to  twenty  feet  long,  two  to  three  feet  broad, 
with  much  waved  and  folded  margin,  outlined  with  two  rows  of  depressed 
spots.  The  spores  form  a  band  in  the  center  of  the  blade.  Found  from 
Cape  Cod  northward  and  on  the  Pacific  coast. 

Li,  saccharina^  the  sea-tangle.  This  species  differs  from  L.  longicruris 
in  having  a  short,  solid  stem  and  narrow,  ribbon-like  lamina.  Stem  three 
•inches  to  four  feet  long ;  lamina  three  to  thirty  feet  long,  six  to  eighteen 
inches  wide,  with  central  band  of  depressed  spots  ]  margin  much  waved ; 
color  olive-green,  semi-transparent.  It  is  named  from  the  saccharine 
matter,  called  mannite,  which  it  contains.  Found  on  northern  shores  of 
the  Atlantic  and  the  Pacific  oceans.     (Plate  XII.) 

L,  digitafa  (^^ fingered").  Stem  one  to  five  feet  long,  thick,  round, 
and  solid;  lamina  oval  at  base,  leathery,  smooth,  brown,  deeply  cleft 
into  segments  of  unequal  breadth.  It  is  named  from  the  hand-like  form 
of  the  lamina.  This  species  is  found  in  Long  Island  Sound,  but  is  not 
common  south  of  Cape  Cod.  The  stem  is  used  by  fishermen  for  knife- 
handles.  Pieces  of  it,  placed  on  the  blades  while  green,  contract  in  dry- 
ing and  become  sohd.     (Plate  XIII.) 

For  the  genera  Macrocystis,  Wereocystis,  Lessonia,  and  Thalas- 

siophyllunif  see  the  Introduction,  pages  35,  36. 

ORDER  DICTYOTACE^ 

Genus  Dictyota 

D,  fasciola.  Fronds  olive-brown,  expanded,  membranaceous,  erect, 
flat ;  many  times  forked  narrow  branches ;  grows  in  tufts  six  to  ten  inches 
long,  matted  at  the  base. 

D.  dichotoma.  Same  as  D.  fasciola,  except  that  the  divisions  of  the 
forked  frond  are  one  eighth  to  one  half  of  an  inch  wide.  Found  in  tide- 
pools  in  Southern  waters.     (Plate  XIII.) 

Genus  Zonaria 

Z,  lobata,  Thallus  flat,  fan-shaped,  but  not  so  rounded  as  in  Padina 
pavonia,  twelve  or  more  inches  in  height,  cleft  irregularly  into  many 


PLATE   XIII. 


Laminaria  digitata. 
Taonia  atomaria. 


Dictyota  dichotoma. 
Padina  pavonia. 


PLATE   XIV. 


Haliseris  polypodioides.  Cutleria  multifida. 

Fucus  vesiculosus. 


OLIVE-GREEN  AND  BROWN  SEAWEEDS  71 

narrow  lobes,  the  clefts  extending  nearly  or  quite  to  the  base  5  olive-green, 
with  concentric  zones  of  darker  color ;  edges  thin  and  bordered  with  a 
dark  line.  Found  in  southern  California  and  in  tropical  and  subtropical 
seas. 

Genus  Taonia 

T,  atomaria.  Spreading,  fan- shaped  frond ;  clefts  irregular  and  not 
extending  to  the  basal  stem ;  spores  arranged  in  dark  wavy  lines  and 
spots  on  the  frond,  giving  it  a  mottled  appearance  and  beautiful  grada- 
tion of  color.     Found  in  tropical  seas.     (Plate  XIII.) 

GrENus  I^adina 

JP,  pavonia,  the  peacock's-tail.  Frond  broadly  fan-shaped  j  sub- 
stance between  membranaceous  and  leathery;  powdery  on  the  outer 
surface  ;  deeply  and  variously  cleft  or  entire  ;  several  laminae  emanating 
from  a  stalk-hke  base ;  each  lamina  fan-shaped ;  concentric  lines  numer- 
ous ;  variegated  in  zones.  This  beautiful  alga  is  always  regarded  as  a 
prize.  It  is  found  on  stones  at  low- water  mark,  and  is  not  uncommon 
south  of  Charleston,  South  Carohna,  but  is  more  luxuriant  in  tropical 
seas.     (Plate  XIII.) 

Genus  Salts eris 
The  sea-endive. 

H,  polyiyodioides.  Fronds  flat,  forked,  notched  on  lower  part ;  di- 
visions about  one  quarter  of  an  inch  wide ;  distinct  midrib )  olive-green ; 
grows  in  tufts.  It  is  found  in  North  and  South  Carohna,  and  is  abun- 
dant on  the  Florida  Keys.     (Plate  XIV.) 


ORDER  CUTLERIACE^ 
Genus  Ctttleria 

C.  multifida.  Frond  erect,  flat ;  branches  in  a  forking  manner ; 
ultimate  branches  fine  and  short,  and  with  branchlets  on  the  tips.  This 
species  resembles  Taonia.    It  is  found  in  Southern  waters.    (Plate  XIV.) 

ORDER  FUCACE-ffi: 

Genus  Jffimanthalia 

H,  lorea,  the  sea-thong.  A  cup-shaped  base,  from  the  center  of 
which  arises  a  flat,  strap -like  frond  one  fourth  to  one  half  of  an  inch 
wide  and  two  to  twenty  feet  long,  branching  dichotomously  (or  by 
forking),  and  dotted  with  pits,  or  conceptacles,  in  which  the  spores  are 
formed.     Found  in  the  extreme  North. 


72  •  MARINE  ALG^ 

Genus  Fucus 

The  rockweeds.  The  plants  of  this  genus  grow  in  thick 
bunches,  and  are  found  in  great  abundance  between  tide-marks. 
The  plants  are  attached  by  sucker-like  disks  to  the  rocks,  from 
which  they  hang  like  fringe  when  the  tide  recedes;  when  it 
rises  they  float  and  sway  in  the  water  in  beautiful  bouquet-like 
forms.  In  color  they  are  brown  or  olive-green,  in  texture  thick 
and  leathery,  but  they  sometimes  expand  into  thin  membranes. 
They  are  many  times  forked  in  the  same  plane,  which  produces  a 
flat  thallus.  They  often  have  a  distinct  midrib.  The  air-vessels, 
whose  function  it  is  to  float  the  plant,  are  disposed  along  the 
midrib,  usually  in  pairs. 

The  species  are  named  according  to  the  divisions  of  the  frond, 
and  the  disposition,  or  presence,  of  the  air-bladders  and  the 
conceptacles,  or  spore-chambers. 

The  conceptacles  congregate  in  particular  portions  of  the  frond 
and  give  its  surface  a  roughness  which  is  very  perceptible ;  such 
portions  are  then  known  as  the  receptacles.  In  Fucus  this 
usually  occurs  on  the  bulbous  extremities  of  the  branches. 
Under  the  microscope  a  section  of  one  of  these  little  pointed 
spots  shows  a  spherical  cavity  filled  with  a  beautiful  arrangement 
of  paraphyses,  or  threads,  some  of  which  hold  spores,  while 
others  protrude  through  a  small  opening  in  the  outer  mem. 
brane.  Conceptacles  are  peculiar  to  the  order  Fucaceae.  In  them 
spore-production  is  carried  on  in  a  manner  as  complicated  as  is 
the  formation  of  seeds  in  flowering  plants.  Although  rockweeds 
are  such  a  conspicuous  feature  of  sea-shore  vegetation,  two  species 
only,  Fucus  vesicidosus  and  AscopliyTlum  nodosum  (formerly  called 
Fucus  nodosus),  are  common  on  the  Atlantic  coast,  and  these  do 
not  occur  south  of  New  York,  owing  to  the  fact  that  a  long 
stretch  of  sand-beach  extends  beyond  that  point. 

F.  vesicidosus.  Midrib  distinct  through  all  the  forked  branches ; 
margin  entire,  often  wavy ;  air-vessels  spherical  or  oblong,  usually  in 
pah's  along  the  midrib ;  receptacles  on  terminal  branches,  which  are 
swollen  and  filled  with  gelatinous  matter,  heart-shaped  or  forked,  in 
oblong  or  pointed  divisions )  frond  tough  and  leathery,  often  two  feet 
long.     (Plate  XIV.) 


PLATE  XV. 


Fucus  serratus.  Fucus  ceranoides. 

Ascophyllum  nodosum. 


PLATE   XVI. 


Phyllospora  Menziesii.  Halidrys  osmunda. 

Sargassum  vulgare. 


OLIVE-GREEN  AND  BROWN   SEAWEEDS  73 

F.  serratus.  Frond  distinctly  toothed  or  serrated  along  the  margin ; 
midrib  conspicuous  through  the  main  axis  and  forked  branchings ;  no 
air-vessels.     This  species  is  rare  on  the  Atlantic  coast.     (Plate  XV.) 

F. furcatus.  Frond  narrow,  tough,  without  air-vessels;  regular 
forked  branching ;  midrib  distinct  below,  inconspicuous  above )  recep- 
tacles long,  narrow,  not  inflated.     Found  from  Boston  northward. 

F,  ceranoides.  Frond  flat,  rather  membranaceous,  or  less  leathery 
than  in  the  preceding  species;  repeatedly  forked;  midrib  not  running 
through  every  division;  no  air-vessels.     (Plate  XV.) 

Genus  Ascophylltitn 

A,  nodosum.  This  species,  formerly  called  Fucus  nodosus,  is  next  to 
Fucus  vesiculosus  the  most  common  rockweed.  Frond  one  to  five  feet 
long,  dark  brown,  strap -like,  leathery ;  width  of  main  stems  one  fourth 
of  an  inch  or  more,  and  uniform  throughout ;  large,  single,  oblong  air- 
vessels  distend  the  frond  at  intervals.  Branches  of  various  length 
emerge  from  the  sides  of  the  main  stem.  Ovoid  or  ellipsoidal  branchlets 
or  receptacles,  single  or  in  groups,  occur  at  intervals  along  the  sides  of 
both  stem  and  branches.  These  fall  off  after  a  time  and  are  found  in 
quantities  in  tide-pools.     (Plate  XV.) 

Genus  I*hyllospora 

F.  Menziesii,  Branching  holdfast ;  short  stem  which  immediately 
divides  into  strap-like  branches  ;  branches  edged  with  leaves  varying  in 
length,  rounded  at  top,  narrow,  stalked  at  base ;  leaves  placed  at  intervals, 
or  crowded  together,  and  interspersed  with  air-vessels  which  are  often 
tipped  with  leaflets ;  stems  expand  at  summit  into  leaf-like  laminge  and 
are  edged  with  leaflets  at  the  base ;  plant  often  one  hundred  and  twenty 
feet  or  more  in  length ;  tough  and  leathery  in  substance.  Very  common 
on  the  Cahfornia  coast.     (Plate  XVI.) 

Genus  Cystoseira 

€,  eocpansa.  Frond  long,  slender,  repeatedly  branched ;  air-vessels 
ellipsoidal  and  ^^  chained"  together  in  the  lower  half  of  the  branches. 
The  plant  grows  in  deep  water,  and  shows  iridescent  colors  when  seen 
through  the  water.    It  is  found  on  the  California  coast. 

Genus  Halidrys 

JET.  osinunda,  the  sea-oak.  Frond  flat,  alternately  toothed  or  indented 
below ;  branched  apex,  bearing  air-vessels  like  long-stalked  pods ;  sub- 
stance leathery.  Found  on  the  coast  of  southern  California.  (Plate 
XVI.) 

Genus  SargassuTn 

Sargassum  is  distinguished  by  its  differentiation  into  stem  and 
leaf,  resembling  in  outward  appearance  the  higher  plants.     It 


74  MARINE  ALG^ 

is  a  tropical  and  subtropical  genus,  and  lias  one  liundred  and 
fifty  species.  Two  of  these,  S.  vulgare  and  8.  Montagnei,  are  found 
as  far  north  as  Cape  Cod.     See  Introduction,  page  34. 

^S'.  vulgare.  Steins  cylindrical  -,  branches  alternate ;  leaves  long, 
narrow,  toothed,  with  short  stalk  and  midrib  ;  minute  dark  spots  on  its 
surface;  air-vessels  small  balls  resembling  berries  set  on  stalks  and 
usually  tipped  with  a  long  point;  receptacles  small,  twig-hke  forms 
in  the  axils  of  the  leaves ;  color  olive-brown ;  plant  one  foot  to  three 
or  more  feet  long.     Common  in  Long  Island  Sound.     (Plate  XVI.) 

S,  Montagnei,  This  species  resembles  S.  vulgare,  but  is  more  slender 
in  aU  its  parts,  and  the  receptacles  are  more  elongated.  From  south  of 
Cape  Cod. 

S,  bacciferum.  Particular  interest  attaches  to  this  species  from  the 
fact  that  it  is  the  one  which  forms  the  floating  vegetation  of  the  Sargasso 
Sea.  It  grows  attached  on  the  Florida  Keys  and  in  the  West  Indies. 
Specimens  are  sometimes  carried  by  the  currents  northward,  and  are 
found  washed  ashore.  It  differs  from  S.  vulgare  in  the  leaves,  which 
are  thicker,  more  attenuated,  and  sharply  toothed,  and  in  having  a 
greater  number  of  air-vessels.  A  branch  of  this  species  brought  from 
the  Sargasso  Sea  had  air-vessels  so  numerous  and  closely  set  that  it 
resembled  a  bunch  of  small  grapes. 


Ill 

RED  SEAWEEDS 
(RHODOPHYCE^  or  FLORIDE^) 


TABLE  SHOWINa  THE  CLASSIFICATION  OF  THE  RED  SEAWEEDS 
DESCRIBED   IN   THIS  CHAPTER 


Orders        Suborders 


NEMALIONACEiE 


Class 
Subclass 

Bhodophyceae  or  Floridese 

(Bed  Seaweeds) 
Genera 


HELMINTHOCLADIEJE 

CHiETANGIE^ 
GELILIEJE 


GIGABTINACE^ 


f  Kemalion 
\  lAagora 
Scinaia 
Gelidium 


Chondrus 
Gigartina 

PJiyllophora 

Stemogra^nme 

Gymnogongrus 

Ahnfeldtia 
Callophyllis 


Species 


N,  multifidum 

S.  furcellata 
G.  corneum 


C,  crispus 

G,  niamillosa 

G,  radula 

G.  spinosa 

G,  microphylla 

J*,  membranifolia 

P,  Brodicei 

S.  interrupta 

G.  Worvegicus 

A.  plicata 
C  variegata 
C,  laciniata 


Iridcea 


76 


Orders        Suborders 


RED  SEAWEEDS 

Genera 

^  Cystoclonium 
Euthora 


RHODOPHYLLIDEiE   /   HhodophylUs 

I  Mhahdonia 

\  Eiichetima 

RHODYMENIACE^ 

r  Gracilaria 

BPHiEROCOOCBJE      [jjyj,^^^ 

IBhoclyinenia 
Lo7nentaria 
Champia 
Chylocladia 
Plocamium 

Nitophyllum 

SELESSERiEiE  <^   Grrififiellia 

Delesseria 


Polysiphonia 


RHODOMELE^ 


Laurencia 

Dasya 

Bostryehia 

Bhodomela 
Chondria 


77 

Species 

r  C  piirpiirascens 
^  C,  cirrhosa 

E,  cristata 

a,  veprecula 

H.  tenera 

It,  Coulteri 

E,  isiforme 

G.  multipartita 
H.  musciformis 
It,  palmata 
L,  Baileyana 
C.  parvula 

C.  articulata 
JP.  coccineum 
JV.  laceratum 

K,  Ituprechteanum 
N,  ptvnctatum 
6r.  Afiiericana 

D,  sinuosa 
D,  alata 

.  D,  Leprietirii 
I*,  fastigiata 
JP.  nigrescens 
I*,  parasitica 
JP,  dendroidea 
I*,  Baileyi 
P,  Harveyi 
J*.  Olneyi 
P,  fibrillosa 
I*,  violacea 

F,  urceolata 
Var.  formosa 
F,  variegata 
P,  Woodii 

L,  pinnatifida 
D,  elegans 
X).  plufnosa 

B,  rivularis 
It,  subfusca 
B,  Bochei 
B,  lariac 

^B,  floccosa 

C,  dasyphylla 
C,  tenuissima 
C.  striolata 


78  MARINE  ALGJE 

Orders        Suborders  Genera 

Callithamnion 

Griffithsia 
JPtilota 
CERAMiEiE  ^  Spyridia 

Ceramium 


Microcladia 

CBTFTONEMIACILS: 

GLOiosiPHONiE^      Gloiosiphouia 

{Halymenia 
Grateloupia 
Prionitis 
i  Pikea 

DUMONTIE^     i   Tj-   7 

(  Halosacciofi 

RHizoPHYLiiDE-aE      Polyides 

C  JPeyssonnelia 
SQUAMAEIEJE  I  PetTocelis 

\  Hildenbrandtia 
Corallina 


CORALLINES 


BANGIAGEiS 


Melohesia 

Bangia 
PorpJiyra 


Species 

C  americanum 

C.  JPylaiscei 
C,  Baileyi 
C,  seirospermum 
C.  byssoideum 
C,  fioccosum 
G.  Bornetiana 
B,  serrata 
jP.  elegans 

B,  densa 

.B,  hypnoides 
S,  filainentosa 

C.  ruhrum 
Var.  proliferiim 
Var,  secundatum 
C.  strictum 

C  diaphanum 
C,  fastigiatutn 
C  tenuissimnm 
Var.  patentissifnum 
M,  Coulteri 
M.  borealis 


G.  capillaris 

BE.  ligulata 
G.  Cutleria 
B,  lanceolata 
B,  Andersonii 
B,  Californica 
H,  ramentaceum 

B,  rotundus 

B,  Bubyi 

B,  cruenta 
H.  rosea 

C.  officinalis 


B.  fusco-purpurea 
B,  vulgaris 
P.  laciniata 


RED   SEAWEEDS 

IN  Khodophyceae,  known  also  as  Floridese  and  Rhodospermeae, 
algae  attain  their  highest  development.-  This  is  marked  by 
the  mode  of  reproduction,  which,  more  nearly  than  in  the  other 
subclasses,  resembles  that  of  flowering  plants.  The  fronds,  how- 
ever, are  not  as  large  and  do  not  as  closely  resemble  stem  and  leaf 
as  do  some  species  of  the  brown  algae. 

The  species  of  this  subclass  are  very  numerous,  and  the  variety 
in  their  fronds,  their  delicate  texture,  and  their  colors,  which  vary 
from  pink  to  purple,  make  them  the  most  attractive  of  the  sea- 
weeds. They  grow  mostly  in  deep  water,  but  are  often  found 
washed  ashore,  and  many  grow  just  below  low- water  mark  and 
on  the  shady  side  of  tide-pools. 

In  the  simplest  species  the  frond  consists  of  branched  cell-rows. 
In  some  of  these  the  filaments  are  so  fine  that  a  pocket-lens  is  re- 
quired to  determine  the  differences  in  branching  and  fully  to 
appreciate  the  beauty  of  the  plant  (CaUithamnion).  Some  have  a 
cell-surface.  In  Delesseria  the  membrane  assumes  the  outline  of 
a  foliage-leaf.  Basya,  which  is  an  abundant  variety,  is  especially 
beautiful  in  its  feather-like  appearance.  The  corallines  are  sin- 
gular in  that  they  are  incrusted  with  lime  and  resemble  corals. 

ORDER   NEMALIONACE^ 

Suborder  HELMiNTHOCLADiE.ffi 

Genus  Nemalion 
The  threadweeds. 

iV.  fnultifidum.  Frond  six  to  twelve  inches  long,  cyhndrical,  solid, 
cord-like,  elastic,  tough,  shiny,  very  gelatinous  j  branches  repeatedly  in 

79 


80  MARINE  ALG^ 

a  wide-forking  manner;  sometimes  a  branch  will  divide  into  several 
parts  at  the  same  point ;  color  dark  brown  or  purple.  It  is  found,  in 
summer  only,  from  Long  Island  Sound  northward,  growing  on  smooth 
rocks  which  are  exposed  to  the  action  of  the  waves. 

Genus  Liagora 

Fronds  filamentous ;  branching  regularly  in  a  forking  manner 
to  the  very  top,  forming  thick  bunches ;  slightly  incrusted  with 
lime,  yet  somewhat  viscid.  It  is  found  in  Florida  and  California, 
and  abounds  in  tropical  waters. 

Suborder  cioetangie^ 
Genus  Scinaia 

S*  furcellata.  Frond  cylindrical,  one  eighth  of  an  inch  in  diameter, 
tapering  at  base,  sometimes  constricted  at  intervals,  regularly  and  sev- 
eral times  forked,  ending  in  short  divisions ;  branches  of  same  length, 
giving  a  level  top ;  two  to  four  inches  high  -,  lake -red.  When  pressed 
the  axis  is  visible,  giving  the  appearance  of  a  flat  frond  with  a  midrib. 
This  species  is  found  in  summer  only,  washed  ashore  from  Cape  Cod 
southward  and  on  the  California  coast.  It  is  not  common.  (Plate 
XVII.) 

Suborder  GELiDiE.ffi 

Genus  Gelidiu^n 

G»  corneum.  Frond  flat  and  homy,  one  inch  to  four  inches  high, 
narrow,  erect,  branched  several  times  in  the  same  plane;  ultimate 
branchlets  club-shaped,  or  swollen  at  the  tips  with  masses  of  spores; 
color  purple-red.  It  grows  in  tufts  on  mud-covered  rocks,  and  on  algae 
at  low- water  mark.  The  typical  form  is  found  in  Florida  and  on  the 
Pacific  coast.  Smaller  plants  are  found  all  along  the  Atlantic  shore.  It 
is  an  extremely  variable  plant,  and  is  often  dif&cult  to  distinguish  on  this 
account.     (Plate  XVII.) 

ORDER  GIGARTINACE.ZE 

Genus  Chondrus 

Carrageen  or  Irish  moss. 

C,  crispiis.  Frond  begins  with  flattened  stem,  which  divides  and 
subdivides  many  times  in  a  broad-forked,  fan-like  manner;  varies 
greatly  in  length  and  breadth  of  divisions,  also  in  size  and  color,  accord- 
ing to  conditions  of  its  habitation.     In  shallow  tide-pools  it  is  pale  and 


PLATE  XVII. 


Scinaia  furcellata. 
Gelidium  Coulteri. 


Gelidiura  corneiini. 
Chondrus  crispus. 


PLATE  XVIII. 


Gigartina  mamillosa. 
Gigartina  spinosa. 


Gigartina  radula. 
Gigartina  microphylla. 


BED   SEAWEEDS  81 

stunted  j  but  under  the  shelter  of  rocks,  in  deep  water,  it  grows  in  dense 
masses  and  is  a  dark  purplish-red  or  reddish-green.  Often  it  appears 
iridescent  when  seen  through  the  water,  with  the  sun  shining  on  it.  It 
is  firm  and  leathery  in  substance.  It  is  an  edible  alga,  and  was  formerly- 
very  generally  used  for  culinary  purposes.  At  Hingham,  Massachusetts, 
large  quantities  are  gathered  as  an  article  of  commerce.  It  is  a  beautiful 
and  very  common  plant  found  from  New  York  northward.    (Plate  XVII.) 

Genus  Gigartina 

Of  the  species  of  this  genus  but  one  is  found  on  the  "eastern 
coast ;  on  the  Pacific  coast  there  are  several,  and  they  are  large 
and  conspicuous. 

6r.  maniillosa.  Frond  three  to  six  inches  high,  one  inch  to  two 
inches  broad,  flat,  leathery,  gelatinous  ;  forking  near  the  base,  then  divid- 
ing and  subdividing  in  the  same  plane ;  segments  more  or  less  wedge- 
shaped  and  with  a  tendency  to  roU  inward;  covered  with  numerous 
small  nipple-like  protuberances  which  contain  the  spores.  These  pro- 
jections distinguish  this  genus  from  CJiondrus,  which  it  otherwise  resem- 
bles, and  with  which  it  grows.  The  color  is  dark  purple.  It  is  found 
from  Boston  northward.     (Plate  XVIII.) 

6r.  radiila.  Frond  flat  and  thick  ;  rising  from  a  short  stem  and 
widening  to  several  inches ;  sometimes  tapering  to  the  top,  sometimes 
blunt  or  divided,  sometimes  cleft  on  the  sides,  but  usually  simple  ;  cov- 
ered with  wart-like  projections ;  color  dark,  livid  red.  It  is  found  on 
the  Paciflc  coast  at  all  seasons,  growing  on  rocks  between  tide -marks. 
Large  specimens  are  one  foot  to  three  feet  long  and  six  to  ten  inches 
wide.     (Plate  XVIII.) 

G,spinosa  ("thorny").  Frond  thick,  leathery;  surface  rough  and 
spiny ;  form  variable,  the  divisions  sometimes  emanating  from  a  broad, 
flattened  base,  or  again  branching  from  a  main  axis ;  all  covered  with 
the  protruding  processes  peculiar  to  the  genus;  color  dark  red,  brown, 
or  purple.     It  is  found  on  the  California  coast.     (Plate  XVIII.) 

G.  microphylla  ("  small-leaved  ").  Plant  rises  from  short,  flat  stem, 
and  rapidly  expands  into  a  flat,  wide,  thin  frond  which  is  simple  or 
divided  into  two  or  three  segments,  each  of  which  tapers  into  a  long, 
pointed  apex;  thickly  covered  with  long,  slender  spines,  and  on  its 
edges  bearing  small,  thin  leaflets ;  color  brownish-red.  It  is  abundant 
on  the  California  coast.     (Plate  XVIII.) 

Genus  Phyllophora 

Leaf  weed.  Fronds  cylindrical ;  branched  stalks  which  expand 
into  rigid,  membranaceous,  simple  or  cleft,  wedge-shaped  laminae ; 
laminae  bear  leaflets  on  their  edges  or  on  their  surface ;  spores  in 
masses  form  projections  on  the  surface,  or  are  on  stalks  at  the 
summit ;  color  dark  red.  Found  washed  ashore  from  New  York 
northward. 


82  MARINE  ALG^ 

P,  menibranifoUa,  Several  stems  rise  from  same  diskj  branches 
expand  into  wedge-shaped,  cleft  or  forked  laminae  j  lobes  bear  on  the 
summit  othei*  laminae  or  leaflets  divided  in  the  same  manner. 

JP.  Brodicei.  Stem  less  branched  and  leaf-expansions  broader  and 
larger  than  in  P.  memhranifolia ;  laminae  wedge-shaped  and  deeply 
lobed.     (Plate  XIX.) 

Genus  Stemogramme 

S»  interrupta.  Frond  a  thin  membrane  repeatedly  forked,  widely 
spreading,  divisions  one  fourth  to  one  half  of  an  inch  wide^  fertile 
plants  have  the  spores  arranged  in  an  interrupted  line  through  the 
center  of  the  segments  resembling  a  midrib ;  frond  two  to  eight  inches 
high  J  bright  red.  It  is  found  on  the  California  coast.  The  illustration 
shows  a  plant  on  which  the  hydroid  Sertularia  pumila  is  growing. 
(Plate  XIX.) 

Genus  Gymnogongrus 

6r.  JSTorvegiciis,  Frond  two  to  four  inches  high,  thin  but  leathery  in 
substance,  flat,  narrow,  divided  in  a  regular  forking  manner ;  spreading 
ends  of  terminal  forks  obtuse  j  axils  rounded  5  spores  form  spherical 
masses  in  the  upper  segments,  and  project  on  both  sides  like  hemi- 
spheres. It  resembles  a  simple  form  of  Chondrus  crispus,  but  is  more 
dehcate.  The  color  is  red  or  purple.  This  species  is  found  in  deep 
tide-pools  from  New  York  northward.     (Plate  XIX.) 

Genus  Ahnfeldtia 

A,  plicata.  Frond  coarse,  stem-like  filaments,  stiff,  wiry,  irregularly 
and  profusely  branched ;  sometimes  regularly  forked  and  upper  seg- 
ments equal ;  entangled ;  six  to  eight  inches  long ;  tufts  several  mches 
in  diameter;  dark  purple  or  black.  Specimens  long  exposed  on  the 
beach  are  faded  to  white.  It  is  very  common  from  New  York  north- 
ward.   (Plate  XIX.) 

Genus  Callophyllis 

C.variegata,  Deeply  cleft,  wide-spreading,  flat,  membranaceous 
frond ;  all  parts  notched  more  or  less  angularly ;  color  dark  to  bright 
red ;  spores  form  hemispherical  warts  on  surface.  Some  varieties  differ 
from  this  one  in  having  long  and  narrow,  and  others  in  having  short 
and  broad  segments.  It  is  a  beautiful  and  common  alga  on  the  Pacific 
coast,  resembling  Euthora  of  the  eastern  coast.     (Plate  XX.) 

C,  laciniata.  Frond  deeply  cleft ;  segments  wedge-shaped.  It  is 
found  on  the  Pacific  coast.     (Plate  XX.) 

Genus  Iridcea 

Frond  rises  from  stalk  and  widens  into  a  flat,  thick,  leathery, 
oval  expansion,  one  to  two  feet  long,  and  one  to  three  inches  broad ; 


S'T. 


.,  ■  >^% 

■4f 

T 

'^ 

*~s 

r 

'  > .  '  .- 

-^5;- 

>^  ^-^. 

~ 

PLATE  XIX. 


Phyllophora  Brodisei. 
Gymnogongrus  Norvegicus. 


Sternogramme  interrupta. 
Ahnfeldtia  plicata. 


PLATE  XX. 


Callophyllis  variegata. 
Iridaea. 


Callopliyllis  laciniata. 
Cystoclonium  cirrhosa. 


RED  SEAWEEDS  83 

simple  or  lobed ;  surface  sometimes  roughened  by  collections  of 
spores  in  dots ;  dark  red,  often  glittering  in  the  water  with  blue 
and  purple  tints.     It  is  found  on  the  Pacific  coast.     (Plate  XX.) 

Suborder  RHODOPHYLLiDE.ffi: 
Genus  Cystoclonium 

C  purptirascens.  The  translucent,  fleshy,  juicy  main  stem,  one 
eighth  of  an  inch  or  less  in  diameter,  runs  through  the  whole  plant ; 
irregularly  branched  all  around  main  stem }  branches  again  branch  in 
same  manner;  branches  attenuated  at  the  base,  and  taper  to  a  long 
point ;  smaller  branches  distended  in  places  by  spores  into  bladder-like 
swellings,  hence  the  name;  color  rose-red  to  dark  purple;  plants  ex- 
posed on  the  beach  often  faded  to  orange  and  white ;  six  to  eighteen 
inches  long.  It  grows  on  rocks  between  tide-marks  as  well  as  in  deep 
water.  With  the  exception  of  Ceramium  ruhrum,  this  is  the  most  com- 
mon red  alga  on  the  eastern  coast  from  New  York  northward.  It  differs 
from  Bhabdonia  in  having  bladdery  branches;  otherwise  it  is  easily 
mistaken  for  it. 

C,  cirrhosa.  Ends  of  branches  terminate  in  spirals  like  tendrils ; 
otherwise  identical  with  C.  purpurascens.     (Plate  XX.) 

GrENUs  JEuthora 

E,  cristata.     Frond  one  inch  to  five  inches  high,  membranaceous, 

broadly  spreading ;  divisions  wide  and  numerous,  ultimately  becoming 
fine  like  minute  branchlets,  each  one  of  which,  under  a  glass,  shows  a 
notch  in  the  tip.  This  beautiful,  bright-red  alga  is  found  in  abundance 
north  of  Capo  Cod.  It  differs  from  Delesseria  alata  in  having  no  midrib 
or  veins.    It  grows  in  deep  water  on  stones,  shells,  and  algse.    ( Plate  XXI. ) 

Genus  ^hodophyllis 

('■'■Rosy  leaf'') 

R,  vepreciila.  Frond  two  to  five  inches  long,  one  fourth  of  an  inch 
to  one  and  one  half  inches  broad,  membranaceous,  forked  ;  margin  cov- 
ered with  leaflets  which  are  in  turn  edged  with  minute  branchlets ;  color 
deep  red.  It  is  found  on  the  northern  New  England  coast.  (Plate 
XXI.) 

Genus  Hhabdonia 

C"  J.  ivand  "^ 

R.  tenera.  Frond  six  to  eighteen  inches  long,  cyhndrical,  fleshy, 
translucent,  juicy ;  irregularly  and  profusely  branched,  branches  long- 
est at  the  base,  erect,  tapering  at  both  ends,  numerous  branchlets ;  some- 
times the  main  stem  runs  through  the  plant,  sometimes  it  is  lost  in  the 


84  MARINE  ALG^ 

branching ;  spore-masses  sometimes  form  knotty  bunches  on  the  side  of 
branches.  It  resembles  a  large  Cystoclonium  purpurascens.  It  is  charac- 
teristic of  Long  Island  Sound,  and  is  not  found  north  of  Cape  Cod,  but 
common  from  there  southward  along  the  whole  Atlantic  coast.  (Plate 
XXI.) 

H.  Coulteri.  This  species  is  common  on  the  Pacific  coast,  and  dif- 
fers from  B.  tenera  in  having  a  more  pronounced  leading  stem,  and 
branches  shorter  and  crowded  at  the  top  of  the  frond. 

Genus  Uucheuma 

E,  isiforme.  Frond  grows  in  tufts  a  foot  or  more  in  diameter ;  stems 
branch  in  all  directions  from  a  central  point,  and  taper  gradually  to  the 
end ',  secondary  branches  spread  to  all  sides ;  all  branches  swollen  at 
intervals  and  armed  with  several  spines  spreading  from  a  conical  base ; 
color  dark  red,  becoming  on  exposure  orange  or  yellow,  and  at  length 
semi-transparent  and  horn-like ;  substance  firmly  cartilaginous.  Abun- 
dant at  Key  West. 


ORDER  RHODYMENIACE^ 

Suborder  sph^rococceje 

Genus  Gracilaria 

G,  multipartita  (''many  times  divided").  Frond  four  to  twelve 
inches  long ;  starting  from  a  short,  cylindrical  stem,  it  flattens  and 
broadens  as  it  rises,  dividing  in  an  irregular,  forking  manner,  or  cleft 
into  palmate  segments  which  broaden  as  they  rise,  and  which  divide  in 
the  same  manner ;  often  cleft  or  branched  on  the  edges ;  conical  spore- 
masses  scattered  over  the  frond  during  July  and  August  j  dingy  purple 
in  color.  The  plant  is  variable  and  sometimes  is  difficult  to  determine.  It 
is  common  from  Cape  Cod  southward.  A  narrow  variety  is  most  abun- 
dant in  Long  Island  Sound.  In  Florida  and  on  the  California  coast  there 
are  broad  varieties  which  may  be  mistaken  for  Mhodymenia.  (Plate 
XXI.) 

Genus  Sypnea 

H,  musciformis  ("moss-like").  Frond  six  to  twelve  inches  long; 
main  stem  running  through,  thick  below  and  tapering  to  the  size  of  a 
bristle ;  much  and  irregularly  branched,  especially  at  the  base  ',  branches 
wide-spreading  in  every  direction,  and  longest  at  the  base ;  branches 
branch  again  in  the  same  manner ;  all  parts  beset  with  short,  horizontal 
spines ;  color  purplish -red.  A  characteristic  feature,  by  which  the  plant 
can  easily  be  distinguished,  is  that  the  ends  of  the  long  branches  are 
naked  and  are  turned  over  like  a  hook,  or  nearly  twisted.  It  is  found 
washed  ashore,  often  in  large,  intricately  twisted  tufts,  from  Cape  Cod 
southward  and  on  the  Pacific  coast. 


PLATE   XXI. 


Euthora  cristata. 
Rhabdonia  tenera. 


Rhodophyllis  veprecula. 
Gracilaria  multipartita. 


PLATE  XXII. 


Rhodymenia  palmata. 
Lomentaria  Baileyana. 


Rhodymenia  palmata. 
Chylocladia  articulata. 


RED   SEAWEEDS  85 

Suborder  rhodymenie^ 
Genus  JRhodymenia 

("  Eedniembrane") 

JB.  palmata  ("  hand-shaped  ").  The  plant  commonly  known  as  dnlse. 
Frond  rises  from  a  disk  in  a  short  cylindrical  stem  which  spreads  into  a 
thin,  broad,  fan-shaped  membrane  six  to  twelve  inches  long  and  four  to 
eight  inches  wide  at  the  top ;  deeply  and  irregularly  cleft  into  many 
wedge-shaped  segments  -,  margin  usually  entire,  but  often  with  leaflets ; 
ends  of  segments  indented,  showing  where  divisions  will  ultimately 
occur ;  color  dark  purplish-red.  It  grows  on  rocks  and  on  algae  below 
low-water  mark,  and  is  common  on  the  New  England  and  California 
coasts.  This  is  an  edible  alga,  and,  like  Chondnis  crispus,  is  an  article  of 
food  in  seaports.     (Plate  XXII.) 

Genus  Lomentaria 

L.  Baileyana.  Fronds  two  to  five  inches  high;  grows  in  tufts; 
filaments  tubular,  irregularly  branched;  branchlets  often  all  on  one 
side ;  branches  and  branchlets  curved  or  arched,  and  tapered  at  both 
ends;  color  brownish-red.  It  is  found  washed  ashore  from  Cape  Cod 
southward.     (Plate  XXII.) 

Genus  ChanijHa 

C,  pai^'ida.  Frond  two  to  six  inches  long,  irregularly  branched ; 
grows  in  tufts ;  filaments  hollow  and  constricted,  so  that  they  appear 
somewhat  like  a  string  of  beads  ;  color  brownish-purple.  It  is  found 
washed  ashore  from  Cape  Cod  southward.     (Plate  XXIII.) 

Genus  Chylocladia 

C*  articulata.  Frond  filamentous,  three  to  twelve  inches  long, 
hollow,  constricted  at  intervals ;  branches  emanate  from  constricted 
joints ;  has  the  appearance  of  a  series  of  pink,  delicate,  oval  sacs. 
(Plate  XXII.) 

Genus  Plocajnium 

P,  coccineum  ("scarlet").  Frond  a  flat,  semi-cartilaginous  main 
stem  one  eighth  of  an  inch,  or  less,  wide,  three  to  eight  inches  long,  with 
alternate  branches  of  unequal  length  emanating  from  the  edges  ; 
branches  have  alternate  branchlets  arranged  in  groups  of  three  or  four 
in  a  row ;  branchlets  have  pinnulse  on  the  upper  side,  like  the  teeth  of  a 
comb  (this  peculiarity  in  branching  makes  the  genus  easy  to  identify) ; 
color  dark  lake-red.  It  is  not  found  on  the  eastern  coast,  but  is  plenti- 
ful in  California.     (Plate  XXIII.) 

Suborder  delesserieje 
Genus  Nitox^hyllinn 

N,  laceratuifi.  Frond  expands  from  narrow  base  and  divides  almost 
at  once  into  long,  narrow,  strap-shaped  segments ;  minute  leaflets,  show- 


86  MARINE  ALG^ 

ing"  a  dot  or  spore-cluster,  occur  at  intervals  on  the  margin ;  plant  six  to 
eight  inches  long  5  thin  and  silky  in  texture.  Abundant  on  the  Cali- 
fornia coast.     (Plate  XXIII.) 

JV.  Huprechteanurn.  Frond  one  foot  to  two  feet  long,  spreading 
from  narrow  base  and  dividing  by  forking  into  deep-cut,  broad,  strap- 
like lobes;  top  divisions  rounded ;  traversed  lengthwise  by  parallel  veins ^ 
margin  of  the  older  parts  bordered  with  a  narrow  frill  of  thin  ruffled 
membrane  which  sometimes  extends  also  over  parts  of  the  surface  of  the 
frond ;  substance  somewhat  rigid ;  color  dark  red  to  purple.  It  is  found 
on  the  California  coast.     (Plate  XXIV.) 

iV.  punctatuni.  Frond  six  to  twenty  inches  long  and  of  the  same 
width,  dividing  in  a  forking  manner ;  crowded  at  top ;  when  in  fruit, 
covered  with  dark  dots ;  substance  thin  and  silky  -,  color  rose-pink.  It 
is  found  on  the  California  coast.   (Plate  XXIV.) 

Genus  Grinnellia 

(Named  for  Mr.  Henry  Grinnell  of  New  York) 

G,  Afnericana,  Frond  a  delicate  membrane,  rose-red  or  purplish 
in  color,  leaf-shaped,  four  to  eight  inches  long,  one  inch  to  four  inches 
wide,  tapering  at  both  ends ;  margin  entire,  but  much  waved ;  a  line  of 
darker  color  through  the  center  resembles  a  midrib ;  masses  of  spores 
form  dots  or  specks  irregularly  over  the  whole  surface;  grows  from 
a  disk  and  short  slender  stem  in  bunches  on  shells  and  stones  in  deep 
water.  It  is  found  washed  ashore  from  Cape  Cod  southward,  and  is 
luxuriant  in  New  York  Bay,  where  it  can  be  found  at  any  season,  but  is 
in  perfection  in  August.     (Plate  XXIV.) 

Genus  Delesseria 

D.  sinuosa.  Delicate,  leaf -like  membrane,  with  midrib  and  veins, 
much  indented  and  resembling  in  general  outline  an  oak-leaf ;  four  to 
eight  inches  long,  two  to  four  inches  broad;  short  stem;  color  dark  red, 
often  flecked  with  green.  It  grows  in  bunches  in  deep  water,  and  is 
easily  distinguished,  since  it  is  the  only  alga  having  a  midrib  and  veins, 
and  resembling  the  leaf  of  a  tree.  It  is  found  washed  ashore  from  Cape 
Cod  northward.     (Plate  XXIV.) 

D.  alata  ("'winged").  Frond  rises  from  short  stem,  which  flattens 
and  divides  irregularly  into  many  branches  and  appears  like  a  midrib, 
all  bordered  with  narrow  membrane  one  eighth  of  an  inch  to  one  inch 
wide;  frond  two  to  four  inches  long;  color  light  red  or  pink.  It  is 
found  on  the  shore  from  Cape  Cod  northward.     (Plate  XXV.) 

D.  Le2^rieurii,  Frond  one  inch  to  two  inches  long,  very  narrow, 
with  delicate  midrib,  forked,  constricted  at  intervals;  branches  start 
from  constricted  points;  thin  and  delicate;  color  purple.  It  is  found 
in  tidal  rivers  near  New  York,  and  is  common  on  the  southern  coast. 
(Plate  XXV.) 

Suborder  rhodomele.e 

The  genera  included  in  this  suborder  are  easily  distinguished 
when  in  fruit  by  the  spore-cases,  or  cystocarps,  which  appear 


PLATE  XXIII. 


Cliampia  parvula. 
Plocamium  coccineuin. 


Champia  parvula,  magnified. 
Nitophylluni  laceratum. 


-V 


^-^*%k 


>v  p^'' 


j 

-^  /     ■ 


PLATE   XXIV. 


Nitophyllum  Ruprechteanura. 
Grinaellia  americana. 


Nitophyllum  punctatuni, 
Delesseria  sinuosa. 


PLATE   XXV. 

Delesseria  alata  Delesseria  Leprieurii. 

Polysiphonia  fastigiata  (on  Ascophyllum).  Polysiphonia  parasitica. 


PLATE   XXVI. 


Polysiphonia  dendroidea. 
Polysiphonia  Harveyi. 


Polysiphonia  dendroidea,  apiece  magnified. 
Polysiphonia  Harveyi,  a  piece  magnified. 


RED  SEAWEEDS  87 

like  little  balls,  either  adherent  to  the  branches,  or  raised  on  short 
stalks.  It  is  the  largest  group,  and  contains  many  of  the  most 
beautiful  of  the  red  alg£e. 

Genus  I^olysiphonia 

('■'■Many  tubes  '") 

A  filament  of  Polysiphonia  appears,  when  seen  under  the  mi- 
croscope, like  a  bundle  of  filaments  made  up  of  a  central  tube,  or 
axis,  surrounded  by  a  number  of  other  tubes.  It  is  by  the  number 
of  these  parts,  called  siphons,  which  vary  in  number  from  four 
to  twenty,  that  the  species  is  determined.  In  some  plants  the 
siphons  are  surrounded  by  a  layer  of  cells,  called  corticating  or 
bark  cells,  which  give  the  filaments  a  solid,  uniform  appearance. 
In  others  the  siphons  are  naked,  and  the  filaments  then  seem 
striped  or  banded  with  color.  It  is  difiScult,  without  a  micro- 
scope, to  be  sure  of  the  classification.  There  are,  however,  other 
characteristics  which  separate  many  of  the  species,  and  some  of 
these  are  described  below.  Two  hundred  species  of  Folysiplionia 
have  been  named  by  algologists.  The  plants  are  plentiful  on  all 
shores,  especially  in  warm,  shallow  waters.  Some  species  are  per- 
ennial, but  most  of  them  are  annuals  and  disappear  in  winter. 

IP.  fastigiata.  This  species  grows  on  Ascophyllum  nodosum  in  a 
globular  tuft,  and  appears  like  a  dark-brown  ball,  one  inch  to  three 
inches  in  diameter.  The  frond  is  a  dense  mass  of  rigid  filaments  branch- 
ing many  times  in  a  forking  manner  and  at  broad  angles.  The  ends  are 
of  nearly  equal  length,  giving  the  plant  a  spherical  shape.  It  is  common 
from  New  York  northward  at  all  seasons,  and  is  easily  recognized  by  its 
general  form  and  place  of  growth.  Egg-shaped  cystocarps,  or  spore- 
cases,  occur  in  the  ends  of  the  terminal  filaments.     (Plate  XXV.) 

-P.  nigrescens.  Frond  three  to  twelve  inches  long,  rigid  below,  soft 
above ;  main  stem  thick  as  a  bristle,  but  not  always  easy  to  distinguish ; 
branches  alternate  and  densely  branched  at  the  ends  ;  siphons  twelve  to 
sixteen  in  number ;  filaments  banded :  color  black  or  verv  dark  brown. 
(Plate  XXVII.) 

JF*.  pardsitica.  Frond  one  inch  to  three  inches  long ;  branched  in  a 
pinnate  or  feather-like  manner ;  filaments  flat ;  all  branches  andbranchlets 
emanating  from  the  edges  and  on  the  same  plane,  giving  a  flat  frond  5 
color  reddish-brown ;  resembles  a  fine  Ptilota  plumosa;  cystocarps  on 
short  stalks.     It  is  found  on  the  California  coast.     (Plate  XXV.) 

P.  dendroidea.  This  is  a  variety  of  the  species  P.  parasitica.  Frond 
four  to  five  inches  long ;  main  branches  placed  at  irregular  intervals, 
but  the  secondary  branches  at  regular  intervals  and  alternate ,  branches 


88  MARINE  ALG^ 

set  at  acute  angles,  giving  the  plant  a  slender  appearance  -,  color  black 
or  dark  brown.     It  is  common  on  the  California  coast.     (Plate  XXVI. ) 

J*.  Baileyi.  Frond  three  to  six  inches  high,  flat ;  branches  emanate 
from  edges  of  the  flat  stems  5  main  branches  wide- spreading  and  irregularly- 
placed,  secondary  branches  regular  and  alternate ;  branchlets  one  eighth 
to  one  half  of  an  inch  long,  covered  on  the  edges  and  around  the  top 
with  incurved  ramuli;  branchlets  broken  off  near  the  base  of  the 
branches  in  mature  plants ;  branchlets  usually  uniform  in  length,  but 
occasionally  one  is  longer  and.  branches  like  the  primary  stem ;  color 
black.     Common  on  the  California  coast. 

P.  Harveyi,  Frond  two  to  six  inches  high;  grows  in  globose  tufts, 
and  has  a  bushy  aspect ;  branches  stiff  and  wide-spreading ;  stems  and 
branches  beset  with  simple  or  branched  spine-like  branchlets;  color 
dark  brown,  or  black  when  dry ;  does  not  collapse  when  taken  from  the 
water ;  cystocarps  on  short  stalks ;  siphons  four  in  number.  It  grows 
on  eel-grass  and  algae,  and  is  common  in  Long  Island  Sound  and  north- 
ward.    Called  locally  niggerhair.     (Plate  XXVI.) 

JP.  Olneyi  (dough-balls).  Fronds  two  to  five  inches  high,  densely 
tufted ;  soft  filaments  of  hair-like  fineness,  much  branched,  and  spread- 
ing ;  when  in  fruit  covered  with  tiny  balls  or  cystocarps ;  siphons  four 
in  number.     It  is  common  from  Cape  Cod  to  New  York. 

JP,  fibrillosa.  Frond  four  to  ten  inches  high,  rather  robust  below ; 
main  stem  quickly  lost  in  a  number  of  prominent  stems  and  spreading 
branches ;  irregularly  and  profusely  branched,  becoming  ultimately  very 
fine ;  numerous  branchlets  covered  with  colorless  fibrils  in  hairy  tufts, 
which  give  it  a  misty  appearance ;  fibrils  so  delicate  that^  they  do  not 
show  well  in  dried  specimens,  but  a  distinct  feature  by  which  to  recog- 
nize the  species  in  the  young  plant ;  color  light  to  dark  brown ;  cysto- 
carps adherent  to  branchlets  or  on  short  stalks ;  siphons  four  in  number ; 
main  branches  only  corticated.  It  is  common  in  summer  on  stones  and 
on  eel-grass,  at  low- water  mark,  from  Cape  Cod  to  New  York.  (Plate 
XXVII.) 

J*,  violacea.  Fronds  six  to  twenty-four  inches  high,  pyramidal  in 
general  outline ;  main  axis  with  long,  wide-spreading  branches  at  the 
base;  branches  rather  robust  and  naked  below,  but  numerous  and  be- 
coming very  fine  and  tufted  at  top ;  cystocarps  adherent  or  on  short 
stalks;  siphons  four  in  number;  main  stems  corticated;  ultimate 
branchlets  show  articulations ;  color  brownish-red.  It  is  common  from 
New  York  northward.     (Plate  XXVIL) 

JP,  iirceolata.  Frond  three  to  ten  inches  high ;  main  stem  bristle- 
like ;  branches  naked  below,  divided  and  subdivided  above ;  branches 
with  short  branchlets  set  at  a  wide  angle  and  often  recurved ;  siphons 
four  in  number ;  shows  articulations ;  color  deep  red.  Name  refers  to 
cystocarp,  which  resembles  a  pitcher.  The  plant  grows  in  loose  tufts, 
and  is  common  from  New  York  northward  and  on  the  California  coast. 

Variety  formosa.  Filaments  soft  and  finer  than  in  P.  urceolata  ; 
branches  long  and  flexuous  ;  articulations  five  to  ten  times  longer  than 
broad;  color  bright  red.  It  grows  in  tufts  sometimes  a  foot  long,  and 
is  found  only  in  the  spring. 

P,  variegata.  Fronds  four  to  ten  inches  high  ;  filaments  thick  as  a 
bristle  below,  and  branched  in  a  forking  manner  to  the  very  top ; 
divided  at  long  intervals  below,  at  the  top  becoming  of  hair-like  fineness 


9  ...,, 


jf,'-^\ 


^n 


^f '■-■-•A  ^/ r*H     ^^" 


^\1 


PLATE  XXVII. 


Polysiplionia  nigrescens. 
Polysiphonia  violacea. 


Polysiphonia  fibrillosa. 
Polysiphonia  Woodii. 


PLATE   XXVIII. 


Lairrencia  pinnatiflda. 
Dasya  plumosa. 


Dasya  elegans. 

Dasya  plumosa,  magnified. 


RED   SEAWEEDS  89 

and  dividing  rapidly,  forming  a  densely  tufted  mass,  which  collapses 
when  taken  from  the  water  j  color  purple'-brown ;  when  mounted,  silky 
in  appearance  -,  filaments  banded ;  siphons  six  in  number.  It  forms 
purple  tufts  on  woodwork  and  on  eel-grass  from  Cape  Cod  southward. 

JP.  Woodii,  Fronds  four  to  six  inches  high ;  branches  flat,  long, 
wide-spreading,  emanating  from  the  edges  in  one  plane ;  younger 
branches  show  articulations ;  ultimate  branchlets  inclined  to  curve  in- 
ward: color  light  brown.  Found  on  the  California  coast.  (Plate 
XXVII.) 

Genus  Laurencia 

L,  pinnatifida.  Frond  flat,  thick,  leathery ;  main  stem  with  oppo- 
site, or  alternate,  branches  of  about  the  same  size  and  character  as 
itself ;  all  pinnatifid,  or  cut  on  the  edges  into  branchlets,  some  of  which 
are  again  divided;  color  bright  purple,  often  unevenly  faded.  It  is 
found  on  the  Pacific  coast.     (Plate  XXVIII.) 

Genus  Dasya 

Chenille-weed. 

J),  elegans.  Fronds  from  six  inches  to  three  yards  long ;  main  stem 
and  branches  cylindrical,  and  all  densely  clothed  with  a  fine,  hair-like 
fringe,  which  gives  the  plant  the  appearance  of  chenille ;  cystocarps  on 
stalks  along  the  branches;  color  pink  or  lake-red.  Out  of  water  it 
seems  like  amass  of  purple  jelly.  It  is  found  at  or  just  below  low-water 
mark  from  Cape  Cod  southward,  and  is  very  plentiful  in  New  York  Bay. 
(Plate  XXVIII.) 

D.  plufnosa.  A  species  found  on  the  California  coast.  The  fringe 
covering  the  stems  consists  of  minute  leaflets  instead  of  hairs,  as  in 
D.  elegans.     (Plate  XXVIII.) 

Genus  Bostrychia 

B,  riviilaris.  Fronds  one  inch  high  ;  color  dark  purple ;  branches 
fine  and  irregularly  bent.  It  grows  where  the  water  is  not  very  salt,  and 
is  found  in  patches  on  submerged  logs  near  New  York.  Common  from 
Charleston,  South  Carolina,  southward.     (Plate  XXIX.) 

Genus  BhodoTnela 

H,  subfusca.  Frond  six  to  eighteen  inches  long;  main  stem  cylin- 
drical, and  branching  widely  on  all  sides ;  branches  longest  at  base  and 
gradually  shortening  to  the  top  of  the  stem  ;  branches  naked  below,  but 
at  the  ends  profusely  branched,  forming  tufts  of  branchlets.  It  is  a 
perennial  plant,  and  changes  in  aspect  with  the  season.  When  mature 
it  is  stiff  and  coarse,  and  when  dry  it  is  quite  black.  Common  from  New 
York  northward. 

-B.  Hochei,  This  species  resembles  in  form  B.  suhfusca,  but  is  much 
finer  and  more  delicate.     In  spring  it  is  a  soft,  fine,  feathery,  and  beau- 


90  MARINE  ALG^ 

tif ul  alga  of  a  rod-brown  color.  It  is  found  washed  ashore,  or  in  deep 
tide-pools,  south  of  Cape  Cod.     (Plate  XXIX.) 

M.  larix.  Frond  cyhndrical,  robust,  six  to  fourteen  inches  high; 
branches  of  unequal  length  standing  out  horizontally  all  around  the  main 
stem ;  clusters  of  branchlets  growing  spirally  around  stem  and  branches. 
Found  on  the  northern  California  coast.     (Plate  XXIX.) 

M,  floccosa.  Frond  four  to  ten  inches  high ;  less  robust  than  M. 
larix  ;  stem  and  branches  flat  and  divided  in  one  plane ;  branches  alter- 
nate 5  ultimate  branchlets  somewhat  incurved ;  color  black.  In  fertile 
plants  the  terminal  branchlets  are  gathered  in  a  mass.  Found  on  the 
California  coast.     (Plate  XXIX.) 

GrENUs  Chondria 

Plants  of  this  genus  are  distinguished  by  having  the  ultimate 
branches  attenuated  at  the  base. 

C  dasyphylla.  Frond  four  to  eight  inches  highj  general  outline 
pyramidal;  branches  alternate  on  main  stem;  stem  and  branches, cov- 
ered with  short,  club-shaped  (blunt  at  top,  attenuated  at  base)  branch- 
lets;  cystocarps,  or  spore-cases,  adherent  to  branchlets  or  on  short 
stalks ;  color  light  or  duU  brown.  It  grows  in  tufts,  and  is  common 
from  New  York  to  Cape  Cod.     (Plate  XXX.) 

C.  tenuissima*  This  species  is  similar  to  C.  dasyphylla,  but  is  more 
slender,  and  the  branchlets  taper  at  both  ends  instead  of  being  club- 
shaped. 

O.  striolata.  A  species  similar  to  C.  tenuissima.  The  branchlets 
bear  secondary  branchlets,  and  the  cystocarps  are  on  short  stalks.  It  is 
plentiful  in  Long  Island  Sound. 

Suborder  ceramike 

Genus   Callithamnion 

These  are  very  beautiful  and  delicate  plants,  growing  in  small, 
soft,  silky  tufts,  bright  red  in  color,  with  darker  dots  along  the 
much-branched  filaments.  There  are  many  species,  and  they  are 
common  on  the  northern  shores  of  both  oceans ;  but  the  different 
species  are  not  easy  to  distinguish  with  the  naked  eye,  and  so  but 
a  few  of  them  are  described  below.  The  special  characteristics  by 
which  the  genus  may  be  recognized  are :  fronds  filamentous,  of 
cobweb  fineness,  one  inch  to  six  inches  long,  much  branched, 
and  closely  crowded  at  the  top ;  brilliant  red  color. 

C.  americanum.  Frond  three  to  six  inches  long,  densely  tufted ; 
filaments  of  extreme  fineness ;  main  branches  alternate ;  much  branched ; 
main  and  secondary  branches  have  pairs  of  branched  ramuli  along  the 


Hi 


-^: 


^''^^• 


PLATE  XXIX. 


Bostrychia  rivularis. 
Rhodomela  larix. 


Rhodomela  Rocliei. 
Rhodomela  floccosa. 


\i 


-^/cs 


0, 


'"\ 


\j^^ 


J". 


PLATE   XXX. 


Chondria  dasyphylla. 
Callithamnion  Pylaisaei. 


Callithamnion  araericanum. 
Callitliamnion  Pylaissei,  a  piece  magnified. 


RED  SEAWEEDS  91 

branches  5  color  rose-pink.  It  grows  on  wharves  and  on  algae  below  low- 
water  mark,  and  is  a  common  and  beautiful  species.  It  is  found  (bat 
only  in  the  spring)  from  New  York  northward,  and  is  abundant  in  Long 
Island  Sound.  ^  (Plates  XXX,  XXXI.) 

C.  JPt/laiscei.  Fronds  three  to  six  inches  long,  more  robust  and 
darker  in  color  than  in  C.  Americamim ;  main  and  secondary  branches 
alternate,  decompound,  all  bearing  at  short  intervals  short  opposite 
branchlets,  which  in  turn  are  covered  with  ramuli.  It  is  found  in  spring 
on  wharves  and  on  algse  from  Boston  northward.     (Plate  XXX.) 

C.  JBcvileyi.  Fronds  one  inch  to  three  inches  long,  with  main  stem  as 
thick  as  a  bristle,  and  running  to  the  top  of  the  frond ;  branches  around 
the  main  stem  longer  at  the  base  than  at  the  apex,  giving  the  plant  a 
pyramidal  outline ;  branches  also  have  a  main  stem  and  short  branches 
•  beset  with  branchlets ;  shrub-like  in  aspect ;  color  purplish-red.  Com- 
mon in  summer  from  New  York  to  Caj^e  Cod. 

C,  seiros2>ertnuni.  Frond  two  to  live  inches  high,  pyramidal  in  out- 
line; has  main  stem  and  alternate  lateral  branches;  branches  have 
secondary  branches  beset  with  delicate,  erect  branchlets ;  hair-hke  in 
fineness.  It  is  common  from  Cape  Cod  southward,  and  is  plentiful  in 
Long  Island  Sound.     (Plate  XXXI.) 

C.  hyssoideiun.  Fronds  one  inch  to  three  inches  long ;  filaments  very 
delicate  ;  main  branches  many  times  di\dded  -,  secondary  branches  long ; 
many  branchlets ;  rose-colored.  It  grows  in  globose  tufts,  and  is  com- 
mon in  Long  Island  Sound.     (Plate  XXXI.) 

C,  fioccosuni.  Fronds  three  to  six  inches  long,  hair-like  in  fineness ; 
flaccid ;  main  branches  sparingly  branched  below ;  numerous  alternate 
branches  above;  all  clothed  with  short,  simple  branchlets;  color  dark 
brownish-red.  The  plant  is  so  exceedingly  fine  that  it  is  difficult  to  dis- 
tinguish the  divisions.  It  grows  on  eel-grass  and  on  algae  below  low- 
water  mark,  and  is  found  from  New  York  to  Cape  Cod.     (Plate  XXXI.) 

GrENus   Griffithsia 

(Named  for  2Irs.  Griffiths,  an  English  algologist) 

These  are  among  the  most  beautiful  of  seaweeds,  because  of 
their  brilliant  color  and  exceedingly  delicate  structure.  They 
grow  in  deep  water,  and  specimens  cast  ashore  are  usually  torn 
and  imperfect,  but  they  may  often  be  gathered  from  deep  tide- 
pools,  and  sometimes  are  found  growing  on  eel-grass.  If  placed 
in  fresh  water  they  discharge  their  coloring-matter  and  quickly 
decompose. 

6r.  Bornetiana,  Fronds  two  to  five  inches  high  ;  filaments  jointed, 
the  divisions  being  long  and  pear-shaped,  growing  shorter  as  they  near 
the  top ;  repeatedly  forked ;  very  soft  and  fragile.  It  grows  in  tufts, 
resembling  corals ;  attains  perfection  in  July,  and  disappears  later  in  the 
summer.  Found  from  Cape  Cod  southward,  washed  ashore  after  storms. 
(Plate  XXXII.) 


92  MARINE  ALG^ 

Genus  Ptilota 

Feather-weed. 

P,  serrata.  Fronds  three  to  six  inches  long",  dark  red  in  color, 
cartilaginous;  flattened  main  stem  with  opposite,  flattened  branches, 
one  of  which  is  minute,  so  that  it  appears  like  alternate  branching ; 
branches  also  have  lateral  branchlets  and  pinnulse,  looking  like  feathers 
or  ferns  ;  all  branching  in  one  plane,  making  a  flat  frond.  It  is  found 
in  the  drift  on  the  beach  after  a  storm,  and  is  common  from  Cape  Cod 
northward,  and  also  on  the  California  coast.     (Plate  XXXII.) 

jP.  elegans.  Narrower  and  more  dehcate  than  P.  serrata,  otherwise 
it  has  the  same  essential  features.  It  is  common  in  summer  from  New 
York  northward,  growing  on  cliffs,  under  Fuciis,  near  low-water  mark, 
and  it  is  also  found  washed  upon  the  beach.     (Plate  XXXII.) 

JP.  densa.  Frond  three  to  twelve  inches  high,  one  eighth  of  an  inch 
wide,  flat,  cartilaginous ;  has  leading  stem  with  flat  alternate  branches  ', 
branches  simple  or  branched  again ;  edges  of  whole  plant  beset  with 
notched,  curved  pinnulse  alternating  with  smaller  feather-like  pmnulse, 
giving  a  dense  edge  to  all  parts  of  the  frond.  It  is  found  on  the  Cali- 
fornia coast.     (Plate  XXXIII.) 

jP.  hypnoides.  Flat,  cartilaginous  main  stem,  much  branched,  and 
all  beset  with  pinnulse.  It  differs  from  P.  densa  in  having  the  alternate 
pinnulae  straight  and  club-shaped,  instead  of  toothed  and  curved,  and 
the  plant  is  not  so  dense  and  compact.  Found  on  the  California  coast. 
(Plate  XXXIII.) 

Genus  Spyridia 

S,  filainentosa.  Fronds  four  to  eight  inches  long ;  filaments  as  thick 
as  bristles,  irregularly  and  repeatedly  branched ;  young  branches  show 
articulations  and  seem  to  be  striped ;  all  branches  clothed  with  short, 
very  delicate,  transparent  filaments,  which  give  the  plant  a  hazy  ap- 
pearance;  color  purplish-red,  which  becomes  brown  when  dried; 
does  not  collapse  when  taken  from  the  water.  It  grows  in  tufts  below 
low- water  mark,  and  is  found  in  the  drift  on  the  beach  from  Cape  Cod 
southward.     (Plate  XXXIII.) 

Genus  Ceramium 

The  pitcher- weed.  This  genus  is  easily  recognized  by  the  ends 
of  the  filaments,  which  are  forked  and  incurved,  resembling  minute 
pincers  or  claws.  The  filaments  are  also  more  or  less  distinctly 
banded.     It  is  widely  distributed. 

C,  rubrum,  red  ceramium.  This  is  a  very  common  and  robust 
species,  found  everywhere,  and  growing  on  everything.  It  is  variable  in 
appearance,  becoming  quite  coarse  when  old,  the  incurving,  claw-Hke 
ends,  which  are  characteristic  of  the  genus,  being  less  pronounced.  It 
branches  by  repeated  forking,  and,  under  the  microscope,  shows  a  bark- 


PLATE  XXXI. 

Callith amnion  americanum,  a  piece  Callithamnion  seirospermum. 

magnified.  Callithamnion  floccosum. 

Callithamnion  byssoideum,  var. 

fastigiatum. 


PLATE  XXXII. 


Griffith sia  Bornetiana. 
Ptilota  serrata,  magnified. 


Ptilota  serrata. 
Ptilota  elegans. 


PLATE   XXXIII. 


Ptilota  densa. 

Ptilota  hypnoides,  magnified. 


Ptilota  hypnoides. 
Spyridia  fllamentosa. 


V.i;f..V!, 


PLATE   XXXIV. 

Ceramium  rubrutn,  var.  proliferum.      Ceramium  rubrum,  top  of  frond  magnified. 
Ceramiuni  diaphanum.  Ceramium    tenuissimum,    var.    paten tissi- 

mum. 


RED   SEAWEEDS  93 

like  layer  of  cells  over  the  whole  surface,  which  make  the  ring-like 
bands  on  the  filaments  less  conspicuous. 

Variety  iwoUferum,  Fronds  beset  on  all  sides  with  simple  or  forked 
branchlets.     (Plate  XXXIV.) 

Variety  secundatufn.  Branchlets  generally  arranged  on  one  side 
of  the  filaments,  or  secund. 

C.  strictuni  ("  straight  ").  Brown  or  purplish-red  filaments  of  hair- 
like fineness,  growing  in  tufts  two  to  six  inches  high,  branching  in  nar- 
row forks  more  and  more  closely  as  they  reach  the  top  of  the  frond. 
There  are  no  principal  branches,  the  filaments  being  of  about  the  same 
diameter  and  regularly  dividing  in  a  forking  manner  throughout.  The 
filaments  are  banded,  the  red  rings  being  relatively  very  narrow.  The 
white  interstices  at  the  base  are  several  times  longer  than  broad,  but 
shorten  gradually  until  at  the  top  they  are  of  equal  length  with  the  red 
bands.     This  species  is  common  from  Cape  Cod  to  New  York. 

C.  diaphanu^n.  This  species  has  comparatively  stout  leading 
branches,  with  secondary  alternate  branches  which  are  finer  than  the 
main  stems  and  divide  in  a  forking  manner  throughout,  and  ultimately 
become  very  fine.  The  color  is  brown  or  purplish -red,  distinctly  banded. 
It  grows  on  eel-grass  and  algse,  and  is  found  from  Cape  Cod  to  New 
York.     (Plate  XXXIV.) 

C.  fastigiatum.  Filaments  of  hair-like  fineness  and  of  about  same 
size  throughout ;  branched  in  regular  forking  manner  throughout, 
the  divisions  being  wide  and  distant  at  the  base,  but  gradually  becom- 
ing closer  and  narrower  as  they  reach  the  top  ;  the  upper  segments 
about  equal,  giving  a  level  top  and  regular  outline  in  mounted  speci- 
mens ;  the  terminal  forks  erect,  or  less  incurved  than  in  other  species ; 
small  points  or  branchlets  emanate  from  some  of  the  nodes  or  joints 
between  the  bands  of  color ;  tufts  globe-shaped,  two  to  five  inches  high ; 
color  lake-red.  This  species  grows  on  mud-flats  and  mud-covered  rocks 
as  well  as  on  algas  and  eel-grass. 

C.  temiissimtmi.  Fronds  two  to  four  inches  high,  densely  tufted; 
the  forked  divisions  very  wide  or  open  ;  color  rose-pink. 

Ya.Yietj  patentissimum.  Fronds  small;  the  forked  divisions  dis- 
tant and  very  wide  open.  A  mounted  specimen  appears  somewhat  like 
network.  The  species  is  common  in  Long  Island  Sound.  (Plate 
XXXIV.) 

Genus  Microcladia 

M,  Coulteri,  Cylindrical,  slightly  flattened  main  stem  ;  branches  set 
uniformly  and  alternately,  short  at  the  base,  gradually  lengthening  as 
far  as  the  center,  and  from  there  diminishing  to  the  apex  of  the  stem, 
giving  a  leaf -like  outhne.  The  same  mode  of  branching  and  the  same 
outline  are  repeated  in  the  branches.  The  ultimate  divisions  are  like 
forked  divisions,  and  are  somewhat  incurved.  The  plant  is  six  to  eight 
inches  high,  and  in  color  is  of  many  shades  of  red  and  pink.  It  is  found 
in  abundance  on  the  Pacific  coast  at  all  seasons.     (Plate  XXXV.) 

M.  borealis.  Branches  and  branchlets  placed  on  one  side  of  arched 
naain  stems ;  secondary  branches  curved  in  opposite  direction  and  bear- 
ing branchlets,  also  divided  on  one  side  only  ;  color  dark  brown.  It  is 
found  on  the  northern  Pacific  coast.     (Plate  XXXV.) 


94  MARINE  AhGM 

ORDER  CRYPTONEMIACEiE 
Suborder   gloiosiphonie^ 
Genus    Gloiosiphonia 

C"  Viscid  tube'') 

G,  cajnllaris.  Frond  six  to  ten  inches  high.,  solitary  or  in  tufts ; 
main  stem  cylindrical,  solid  above,  hollow  below ;  from  about  an  inch 
above  the  base  densely  beset  with  short,  wide-spreading  branches 
arranged  evenly  and  all  around  the  stem ;  branches  again  branched  in 
the  same  way ;  branches  and  branchlets  attenuated  at  base  and  apex ; 
soft,  tender,  juicy ;  shrinks  much  in  drying.  The  species  is  easily  recog- 
nized by  its  delicate  gelatinous  substance,  tapering  branchlets,  and 
brilliant  red  color.  It  is  found  in  early  summer  in  tide-pools  on  the 
New  England  coast. 

Suborder  GtEATEloupieje 
Genus  Halyfnenia 

S.  ligulatci.  Frond  membranaceous,  repeatedly  and  regularly 
di^'ided  in  a  forking  manner ;  the  larger  divisions  one  half  of  an  inch 
wide  and  growing  very  narrow  at  the  top;  four  to  five  inches  high, 
spreading  in  a  fan-shape ;  color  rose-red.     It  is  found  at  Key  West. 

Genus  Grateloupia 

G.  Ciitleria,  Frond  coarse,  flat,  variable  j  either  simple,  long,  and 
narrow,  or  short  and  broad,  tapering  at  both  ends,  or  blunt  at  the  apex, 
or  deeply  cleft  into  many  segments;  sometimes  with  leaflets  along  the 
edges;  height  two  to  three  feet;  color  reddish-brown;  in  fading, 
changes  to  purple  and  green,  and  may  be  variegated.  When  simple, 
the  plant  resembles  Iridma.     Found  on  the  northern  California  coast. 

Genus  Prionitis 

F.  lanceolata.  Frond  narrow,  flat,  smooth;  leathery  stems,  which 
branch  irregularly  and  sparingly  from  the  edges ;  branches  bordered 
with  lance-shaped  leaflets ;  color  dark  brownish-red  ;  plant  ten  or  more 
inches  high,  and  varies  considerably.     (Plate  XXXV.) 

There  are  other  species,  among  them  JP.  Anderson  ii  (Plate  XXXVI) ; 
all  are  easily  distinguished  by  the  lance-shaped  leaflets.  Common  on 
the  Pacific  coast. 

Su^border  DTJMONTIE^ 
Genus   Pikea 

P,  Californica,  Divisions  of  frond  thick,  narrow,  cartilaginous; 
central  axis  one  eighth  of  an  inch  to  one  inch  wide,  three  to  four  inches 
high,  thickly  set  with  similar  branches  irregularly  placed ;  aU  bordered 


PLATE   XXXV. 


Microcladia  Cotilteri. 
Microcladia  borealis. 


Microcladia  Coulteri,  magnified. 
Prionitis  lauceolata. 


PLATE  XXXVI. 


Prionitis  Andersonii. 
Halosaccion  ramentaceum. 


Pikea  Califomica. 
Poly  ides  rotundus. 


RED  SEAWEEDS  95 

with  nmnerous  forward-pointirig  branchlets,  which  in  turn  have  spine- 
hke  ramuh  of  various  lengths ;  frond  flat,  broadly  spreading ;  dark  red. 
It  is  common  at  all  seasons  on  the  California  coast.     (Plate  XXXVI.) 

Genus  Halosaccion 

H,  ramentaceum.  Fronds  brownish-purple,  six  to  fourteen  inches 
long,  coarse  and  cartilaginous,  cylindrical,  hollow,  compressed,  attenu- 
ated at  the  base;  more  or  less  covered  with  simple  or  forked  hollow 
branches  half  the  size  of  the  main  stem.  In  exposed  pools  the  plants  are 
short  and  densely  branched  j  in  sheltered  places  they  are  larger  and 
more  delicate  in  texture.  They  are  common  on  the  northern  New  Eng- 
land and  northern  California  coasts.     (Plate  XXXVI.) 

Suborder  RHizoPHYLLiDiLE 

Genus  I^olyides 

JP,  rotundus.  Frond  three  to  six  inches  high,  cylindrical,  cartilagi- 
nous, repeatedly  forked,  ends  obtuse ;  spore-masses  form  numerous  lighter- 
colored  excrescences  on  the  upper  divisions  of  the  frond;  dark  red. 
Common  from  New  York  northward,  in  deep  pools  and  washed  ashore. 
(Plate  XXXVI.) 

Suborder  squamarieje 

Genus  I^eyssonnelia 

JP.  Duhyi,  Frond  completely  adherent  to  the  rock  or  stone  on  which 
it  grows ;  color  dark  purple ;  somewhat  calcareous ;  redder  and  thicker 
than  next  species.  It  is  found  at  low-water  mark  or  in  deep  water  on 
the  northern  New  England  and  northern  California  coasts. 

Genus  Petrocelis 

P".  cruenta.  Frond  closely  adherent,  forming  dark-purple  velvety 
patches  of  indefinite  outline  on  rocks  and  stones.  Common  north  of 
Cape  Cod. 

Genus  Sildenhrandtia 

a,  rosea.  Forms  continuous  pink  incrustations  of  considerable  ex- 
tent on  stones  and  rocks  at  low-water  mark.     Common  everywhere. 

Suborder  corallines 

The  genera  of  this  suborder  are  characterized  by  a  calcareous 
or  stony  incrustation  of  the  fronds,  which  gives  them  the  appear- 
ance of  corals.     Most  of  the  species  are  tropical. 


96  MARINE  ALG^ 

Genus   Corallina 

C"  Coral-like") 

C,  officinalis,  common  coralline.  Frond  grows  from  a  disk  in  tufts 
more  or  less  dense.  The  plant  is  rigid,  and  seems  like  jointed,  branched 
coral.  The  articulations  are  cylindrical  at  the  base,  wedge-shaped  and 
flattened  above.  Branches  emanate  from  the  top  of  the  articulations. 
The  color  varies  from  reddish-purple  to  gray-green,  and  is  often  bleached 
white  when  exposed  to  the  sun.  Common  in  tide-pools  and  on  rocks 
at  low-water  mark  from  New  York  northward.     (Plate  XXXVII.) 

Genus  Melohesia 

This  genus  will  attract  attention,  although  it  cannot  be  gathered. 
It  is  a  thin,  brittle,  scaly  substance  of  indefinite  form,  which  ex- 
pands horizontally  and  resembles  a  lichen.  It  forms  brown  and 
pink  crusts  on  other  alga3  and  on  rocks,  stones,  and  shells. 

ORDER  BANGIACE^ 
Genus  Bangia 

B,  fusco- purpurea  ('^  brown-purple  ").  Fine,  hair-like,  unbranched, 
dark-purple  filaments,  one  inch  to  six  inches  long.  It  grows  in  large 
patches  on  rocks  and  woodwork,  floating  free,  but  falling  into  soft, 
silky,  fleece-like  masses  when  left  by  the  tide.  Common  on  northern 
shores.     (Plate  XXXVII.) 

Genus  Porphyra 

(^'■Purple  dye'''') 

This  plant,  except  in  color,  is  like  the  green  alga  TJlva.  In 
color  it  is  purple  of  various  shades.  The  species  are  named  from 
variations  in  the  outline  of  the  frond.  They  are  found  every- 
where, and  throughout  the  year.  The  plants  are  edible,  being 
the  laver  of  commerce,  eaten  principally  by  the  Chinese,  who 
make  them  into  soup. 

J*,  vulgaris.  Frond  a  broad,  thin  membrane  of  purple  color,  three 
to  twelve  inches  across j  margin  much  waved;  sometimes  attached  at 
the  center,  often  widely  expanded  and  folded,  sometimes  deeply  lobed. 
(Plate  XXXVII.) 

J?,  laciniata.  Differs  from  P.  vulgaris  in  being  divided  into  narrow 
segments  or  into  wavy,  ribbon-hke  forms.     (Plate  XXXVII.) 


PLATE   XXXVII. 


Corallina  officinalis. 
Porphyra  vulgaris. 


Bangia  fusco-purpurea. 
Porphyra  laciniata. 


Paet  II 
MAEINE   INVERTEBEATES 


I 

PORIFERA 

(SPONGES) 


TABLE  SHOWING  THE  CLASSIFICATION  OF  THE  SPONGES 

DESCRIBED  IN  THIS  CHAPTER 

Pliylum  and  Class 

PORIFERA 

Subclass 

Calcarea 

Genera 


Order 
H£TEBOC(ELA 


Families 


SYCONIDiE 


Grantia 
Lencosolenia 


Species 

6r.  ciliata 
L,  botryoides 


Subclass 

Non-Calcarea 
CHONDROSPONGLffi 

r  Suherites 
suBERiTiDiE    <  Polymastia 
^  Cliona 

j  Esperiopsis 


CORNACUSPONGLffi 

DESMACIDONIDJE 

HETERORRHAPHIL^ 


}  Microciona 


Tedania 


S,  compacta 
JP,  robusia 
C.  sulphurea 

E.  qiiatsinoensis 
M.  prolifera 


HOMORRHAPHiDiE       HallchondHa     H,  panicea 


Chalinopsilla 


[Euspongia 


SPONGIDJE 

Subfamily 
EUSPONGIN^ 


Hippospongia 


SPONGID^ 

Subfamily 
STELOSPONGINJE 


Hircinia 


100 


O.  oculata 
C  arbuscula 
E,  ojjicinalis 
Var.  adriatica 
Var.  Tnollissima 
Var.  rotunda 
Var.  dura 
JET.  equina 
Var.  cerebriformis 
Var.  meandriformis 
Var.  elastica 
H.  canaliculata 
Var.  gossypina 
Var.  flabellum 

JOT.  campana 


SPONGES 

THERE  are  many  animals  wliich  consist  of  but  one  cell.  These 
are  called  Frotozoa,  and  comprise  the  Infusoria  and  other  mi- 
croscopic organisms.  The  animals  next  higher  in  the  scale  are 
Metazoa,  or  multicellnlar  animals,  and  the  first  group  of  this  sub- 
division is  Porifera,  the  sponges,  the  lowest  of  the  many- celled 
animals. 

For  a  long  time  sponges  occupied  a  disputed  ground  between 
the  animal  and  vegetable  kingdoms.  Aristotle  was  the  first  to 
point  out  that  a  sponge  is  not  a  plant.  The  assertion  was 
doubted  and  combated,  but  at  last  the  animal  nature  of  the  sponge 
was  established.  Sponges  were  then  believed  to  be  colonies  of 
one-celled  animals,  but  finally  it  was  decided  that  they  were  indi- 
viduals with  cells  of  different  kinds  that  performed  functions 
analogous  to  those  of  higher  organisms. 

The  sponge,  as  commonly  seen,  is  only  the  skeleton  or  frame- 
work, so  to  speak,  of  the  living  animal.  In  its  natural  state  it  is 
a  very  different-looking  object.  Its  entire  surface  is  covered  with 
a  thin  slimy  skin,  usually  of  a  dark  color,  which  is  perforated  with 
holes  corresponding  to  the  apertures  of  the  canals.  The  organic 
portion  of  the  sponge  is  a  soft,  jelly-like  substance  composed  of 
three  layers— the  external  {ectoderm),  the  internal  (endoderm),  and 
the  middle  {mesoderyn).  The  external  layer  is  composed  of  flat 
cells.  The  endoderm  has  cylindrical  cells,  each  one  of  which  has 
a  flagellate  hair.  The  main  mass  of  the  body,  the  mesoderm  or 
middle  layer,  is  made  up  of  cells  having  various  functions,  some 
being  concerned  in  the  formation  of  framework,  some  in  diges- 
tion, and  some  in  reproduction. 

The  framework  is  secreted  in  the  mesoderm,  and  in  different 

101 


102 


MARINE  INVERTEBRATES 


Various  forms  of  sponge-splcules. 


genera  consists  respectively  of  a 
horny  or  silicious  or  calcareous  i 
substance,  or  of  the  first  two  of  .^ 
these  substances  combined.  The 
sponge  of  commerce  has  the 
first  kind  and  is  composed  en- 
tirel}^  of  exceedingly  fine  flexible 
fibers  of  a  horny  substance  called 
spongin.  In  other  species  the 
spongin  is  intermixed  with  spic- 
ules of  silica,  or  of  carbonate 
of  lime,  in  various  shapes.  In  the  sponges,  so  much  valued  as 
curiosities,  called  '^Venus's  flower-basket"  and  "glass-rope 
sponge,"  the  framework  is  composed  of  silicious  spicules  alone. 
The  spicules  have  a  great  variet}^  of  shapes,  being  rod-like, 
knobbed,  three-pointed,  six-pointed,  anchor-like,  etc.,  and  are  a 
feature  in  the  classification  of  sponges. 

The  sponge  is  traversed  throughout  by  a  canal  system,  con- 
sisting of  a  series  of  tubes  through  which  water  circulates,  carry- 
ing air  and  food  to  the  ani- 
mal. The  exterior  of  the 
sponge  has  numerous  small 
pores  and  a  comparatively 
few  large  openings.  The  fine 
pores  are  inhalent,  taking  in 
and  straining  the  water  of 
its  coarser  floating  material, 
and  then  passing  it  through 
perforations  in  their  sides 
into  sacs  lined  with  peculiar 
cylindrical  cells  having  flagel- 
late hairs,  each  hair  having  a 
collar  at  its  base.  These 
cells,  called  cJioanocytes,  re- 
semble independent  animals 

To  iUustrate  choanocytes  (C/i):   sectioL  o.  a  cal-       of     thc     ProtOZOCl,     kuOWU      aS 
careous  sponge.     JEct,   ectoderm ;   3Ies,  mesoderm ;  . 

i\r,  calcareous  spicule ;  ^z,  ovum.  flagellCBte     InfuSOrid     OY     CJlOa- 


SPONGES 


103 


noflagellata.  They  take  in  and 
digest  food  and  eject  excre- 
ment from  the  area  inclosed 
by  the  collar.  The  cilia  (hairs) 
by  their  constant  movement 
create  currents  which  keep  the 
water  in  motion.  Water,  then, 
is  taken  through  the  pores  into 
the  first  or  incnrrent  canals  j 
thence  it  is  passed  into  the 
ciliated  chambers,  and  thence 
into  the  excurrent  canals,  and 
out  through  large  passages 
terminating  in  large  openings 
called  osciila,  or  craters.  The 
canal  systems  vary.  In  some 
species  they  become  quite  com- 
plex. 

Sponges  vary  greatly  in 
shape,  size,  color,  surface,  rigid- 
ity, canal  systems,  and  skel- 
eton. They  are  cake-shaped, 
tubular,  digitate,  palmate,  cup- 
shaped,  vase-shaped,  cone- 
shaped,  spherical,  hemispheri- 
cal, pedunculate,  etc.,  their 
shapes  depending  upon  wheth- 
er their  growth  is  uniform  or 
is  excessive  in  a  horizontal  or 
in  a  vertical  direction.  When 
they  grow  evenly  in  both  direc- 
tions massive  uniform  shapes 
arise.  If  lateral  growth  pre- 
dominates, broad,  low,  and  in- 
crusting  shapes  result.  When 
there  is  an  excess  of  vertical 
growth  the  forms  are  digitate ; 


Canal  system  of  Sycon  gelatinosum.  Transverse 
section  through  the  wall  of  a  cylinder  (parallel 
with  the  course  of  the  canals),  shomng  one  in- 
cuiTent  canal  (IC)  and  one  radial  (i?)  throughout 
their  length;  s?:*,  triradiate  spicules;  sp',  oseate 
spicules  of  dermal  cortex  (dc) ;  S2)",  tetraradiate 
spicules  of  gastral  cortex  (gc) ;  ec,  ectoderm;  en, 
endoderm ;  pm,  pore-membrane ;  pp,  prosopyle ; 
cq),  apopyle;  cli,  diaphragm;  exc,  exciirrent  pas- 
sage; PG,  paragastric  cavity;  em,  early  embryo; 
em',  late  embryo.  (The  arrows  indicate  the  course 
of  the  water  through  the  sponge.) 


104  MARINE   INVERTEBRATES 

but  if  vertical  growth,  is  not  greatly  in  excess  and  is  restricted  to  the 
marginal  part,  cnp-shaped  forms  result,  and  tubular  forms  when 
lateral  growth  is  particularly  restricted.  "In  some  varieties  tubular 
masses  coalesce  -,  sometimes  flat  forms  unite  in  intricate  com- 
pressed folds.  Differences  in  rapidity  of  vertical  growth  make 
undulations  more  or  less  marked,  producing  lobes  and  protuber- 
ances. Sometimes  narrow  vertical  growth  is  retarded  and  hori- 
zontal growth  predominates,  forming  various  shapes  on  apparent 
stems. 

Many  of  the  horny  sponges  are  colored,  in  shades  of  yellow, 
brown,  red,  and  violet  j  some  are  black. 

Sponges  are  divided  into  two  classes,  the  Calcarea  and  Non- 
Calcarea.  The  former  have  calcareous  skeletons,  which  make 
them  hard  and  rigid ;  the  latter  have  skeletons  of  spongin-fiber 
or  of  silicious  spicules,  or  of  the  two  combined. 

All  sponges,  with  the  exception  of  one  family  (the  Sj^ongiUidce, 
which  live  in  fresh  water),  are  inhabitants  of  the  sea,  and  live  at 
various  depths.  The  sponges  of  commerce  belong  to  the  Isf on- Cal- 
carea and  are  all  confined  to  the  genus  Spongia.  In  this  genus  the 
skeleton  is  more  or  less  flexible,  being  composed  of  spongin. 
They  are  shallow-water  species,  are  confined  to  seas  where  the 
waters  are  of  comparatively  uniform  high  temperature,  and 
flourish  best  when  protected  by  reefs  and  islands. 

There  are  fisheries  for  sponges  in  the  waters  of  the  West 
Indies,  the  Bahamas,  on  the  southern  and  western  coasts  of 
Florida,  and  in  the  Mediterranean  and  Red  seas.  Those  of 
the  Mediterranean  surpass  in  quality  the  sponges  of  our 
coasts. 

Five  species  of  commercial  sponges  are  taken  from  Florida 
waters.  They  are  graded  by  the  trade  in  the  order  of  their  im- 
portance, as  the  ''  sheepswool,"  ^^  yellow,"  ^'  grass,"  "  velvet,"  and 
"  glove."  The  fishing  for  sponges  is  done  from  small  boats,  two 
persons  manning  each  boat.  One  man  sculls,  while  the  other, 
using  a  water-glass,  scans  the  bottom.  The  water-glass  is  a  box 
with  a  pane  of  glass  on  the  bottom.  If  the  glass  is  held  below  the 
surface  and  the  face  is  placed  in  the  box,  the  observer  is  enabled 
to  see  with  some  distinctness  the  bottom  at  a  considerable  depth 


SPONGES  105 

in  these  clear  waters.  The  sponges  are  dragged  up  by  hooks— a 
primitive  method  which  restricts  the  fishing  to  shallow  water,  the 
fishing  here  being  in  water  not  deeper  than  thirty  feet,  but  usually 
three  to  twenty  feet.  The  sponges  are  "killed"  by  being  exposed 
on  the  beach  for  several  daysj  they  are  then  placed  in  ^'crawls/' 
or  pens,  where  they  are  washed  by  the  action  of  the  waves  for 
about  a  week ;  then,  if  clean,  they  are  dried,  assorted,  strung  on 
cords,  pressed  and  baled  for  shipment.  The  sponge-fisheries  are 
of  considerable  value,  and  much  attention  is  being  given  to  the 
subject  of  artificial  propagation.  It  is  thought  that  such  beds 
could  be  subjected  to  the  regulations  which  govern  oyster-beds. 
Already  the  planting  of  sponges  has  been  shown  to  be  practi- 
cable. The  living  sponge  is  cut- to  pieces,  and  the  cuttings  are 
placed  in  favorable  localities.  Pieces  planted  in  Florida  waters 
attain  a  marketable  size  in  one  year. 

Sponges  reproduce  by  eggs  formed  in  the  mesoderm.  The 
eggs  escape  as  ciliated  spheres  and  swim  about  until  they  find  a 
place  on  which  to  attach  themselves.  As  soon  as  they  become 
fixed  they  grow  with  much  rapidity  into  mature  individuals. 

Some  species  seem  to  prefer  association  with  other  animals  and 
live  as  commensals  with  crabs.  The  crab  Dromia  is  always  con- 
cealed under  a  sponge,  which  grows  upon  its  back.  Spider-crabs 
are  often  overgrown  with  sponges  as  well  as  seaweeds.  In  this 
case,  however,  the  crab  finds  and  plants  the  sponge  himself. 
Aphjsella  violacea  overgrows  w^orm-tubes.  Many  sponges  afford 
shelter  to  numerous  small  animals  which  bore  into  their  bodies 
for  protection,  no  animal  seeming  to  feed  upon  the  sponge. 

Sponges  may  be  found  in  tide-pools,  on  the  under  side  of 
stones,  on  seaweeds,  and  so  on.  A  small  bright-red  incrusting 
sponge  with  irregular  lobe-like  branches  is  common  on  the  New 
England  coast ;  a  thin  yellow  incrusting  sponge  also  is  found  on 
the  under  side  of  stones.  Grantia  ciliata,  a  small  urn-shaped 
species,  having  a  large  aperture  at  the  summit,  is  found  in  tide- 
pools. 

Perhaps  the  most  singular  in  habit  of  any  sponge  is  Cliona 
sidphurea,  the  boring-sponge,  a  common  species  found  from  Cape 
Cod  to  South  Carolina  and  abundant  in  Long  Island  Sound.     It 


106  MARINE  INVERTEBRATES 

is  bright  sulphur-yellow  in  color,  grows  in  irregular  masses  of 
considerable  size  and  fine  texture,  and  has  low  wart-like  promi- 
nences. It  lives  on  shells  spreading  over  both  surfaces,  at  first 
forming  little  burrow^s,  but  eventually  penetrating  the  shell  in 
every  direction,  honeycombing  and  at  last  completely  destroying 
it  by  absorption.  Sometimes  it  settles  upon  living  shells  and 
greatly  irritates  the  animal,  which  constantly  secretes  new  lime 
to  cover  the  perforations  in  its  shell. 

These  sponges  are  an  important  factor  in  the  economy  of  the 
sea,  as  they  disintegrate  dead  shells,  which  would  otherwise 
accumulate  in  vast  quantities. 

SUBCLASS   CALCAREA 

Genus  Grantia 

G*  eiliata.  Small,  urn-shaped  or  oval,  with  large  aperture  at  the 
summit,  surrounded  by  a  circle  of  projecting  spicules.  It  is  found  in 
tide-pools  and  on  piles  of  wharves  from  Rhode  Island  northward. 

GrENus  Leucosolenia 

L,  botryoides.  Tubular,  branched.  Occurs  in  the  same  places  as 
Grantia  ciliata. 

SUBCLASS   NON-CALCAREA 

Genus  Suberites 

S,  compacta.  Elongated,  compressed  masses,  sometimes  in  several 
lobes;  attached  by  one  edge;  texture  fine,  firm,  compact;  surface 
smooth ;  color  bright  yellow.  It  grows  on  sandy  bottoms,  and  is  com- 
mon in  shallow  water  south  of  Cape  Cod.     (Plate  XXXVIII.) 

Genus  JPolymastia 

p.  robusta.  When  young  it  forms  yellowish- white  incrustations 
over  shells  and  stones ;  later  it  grows  into  long,  slender,  round,  tapering, 
finger-like  projections.  Found  on  the  northern  New  England  coasts  in 
deep  water. 

Genus  Cliona 

C.  sulphurea,  the  boring-sponge.  Irregular  massive  form  of  firm 
texture;  surface  covered  with  scattered  low  wart-like  prominences 
about  one  eighth  of  an  inch  in  diameter ;  bright  sulphur-yellow.  It 
destroys,  by  absorption,  vast  quantities  of  dead  shells. 


PLATE  XXXVIII. 


Haliehondria  panicea. 
Hircinia  campana. 


Suberites  compacta. 
Esperiopsis  quatsinoensis  (found 
on  the  sea-beaches  of  Alaska). 


PLATE   XXXIX. 

Microciona  prolifera.  Chalinopsilla  arbuscula. 

Chalinopsilla  imitans.  Euspongia  officinalis,  var.  tuba.  Chalinopsilla  oculata. 


SPONGES  107 

Genus  Microciona 

M,  prolifera.  When  young  this  species  forms  bright-red  incrustations 
over  shells  and  stones ;  later  it  rises  into  irregular  lobes  and  tubular  prom- 
inences. When  fully  developed  it  is  profusely  branched  in  a  forking 
manner.  The  branches  are  more  or  less  flattened,  and  often  are  palmate 
at  the  ends.  It  grows  in  clusters  six  inches  in  diameter,  of  a  dark 
orange-red  color.  When  dry  it  is  grayish-brown,  brittle,  and  bristly. 
It  is  found  from  Cape  Cod  to  South  Carolina,  and  is  abundant  in  Long 
Island  Sound.     (Plate  XXXIX.) 

Genus  Tedania 

Irregular,  uneven,  pale-yellow  masses  spreading  over  seaweeds ; 
oscnla  scattered  irregularly  over  the  surface ;  texture  close. 

Genus  SEalichondria 

H.  panicea,  crumb-of -bread  sponge.  It  resembles  the  crumb  of 
bread,  and  is  found  cast  up  on  all  beaches.     (Plate  XXXVIII.) 

Genus  Chalinopsilla 

C,  oculata,  the  finger-sponge.  Stem  stout,  more  or  less  flattened, 
dividing  at  the  upper  end  into  branches  which  vary  in  form  and  thickness, 
being  finger-like  or  more  or  less  compressed  lobes  ;  oscula  scattered  over 
the  smooth,  undulating  surface ;  texture  rather  hard,  but  delicate  ;  color, 
when  living,  duU  orange-red;  when  the  animal  matter  is  removed, 
white.  The  species  is  found  in  shallow  and  deep  water  from  New  York 
to  Labrador.     Common  in  Massachusetts  Bay.     (Plate  XXXIX.) 

C»  arhuscula.  Profusely  branched  in  a  forking  manner  from  close 
to  the  base ;  branches  slender ;  clusters  six  to  eight  inches  high  and 
about  the  same  in  breadth ;  color  buff  or  gray  when  living,  yellowish- 
white  when  free  from  animal  matter ;  texture  finer  and  more  delicate  than 
that  of  C.  oculata.  It  is  found  in  shallow  water  from  Cape  Cod  to  North 
Carolina,  and  is  abundant  in  Long  Island  Sound.     (Plate  XXXIX.) 

Genus  Euspongia 

E,  officinalis.  This  is  one  of  the  commercial  sponges  and  is  known 
as  the  ''  glove-sponge."  It  is  the  one  of  least  marketable  value,  having 
inferior  elasticity  and  becoming  brittle  with  age ;  yet  a  Mediterranean 
sponge  of  the  same  species,  variety  adriatica,  is  of  the  finest  quality  and 
greatest  value.  This  singular  fact  demonstrates  that  the  quality  of 
sponges  depends  largely  upon  physical  conditions.  E.  officinalis  has 
an  average  height  of  five  to  six  inches.  It  grows  on  rocky  bottoms 
in  shallow  water  on  the  east  coast  of  Florida.  This  species  has  a  num- 
ber of  varieties  of  various  forms;  some  are  dome-shaped,  others  tubular, 
rotund,  flabellate,  etc.  The  surface  is  covered  with  fine  tufts  and  is 
generally  free  from  ridges.     On  the  sides  are  numerous  small  apertures. 


108  MARINE  INVERTEBRATES 

and  one  or  more  large  oscula  occur  on  top.  The  color  of  the  living 
sponge  is  black.     (Plates  XXXIX,  XL.) 

E,  officinalis,  variety  adt^iatica.  More  or  less  globose ;  sometimes 
attached  by  a  broad  base,  sometimes  by  a  short  stem  ;  latter  form  more 
or  less  club-shaped;  oscula  scattered  over  upper  surface.  Found  in 
the  West  Indies  and  the  Mediterranean.     (Plate  XL.) 

E,  officinalis,  variety  niollissima,  the  Levant  toilet-sponge.  Gener- 
ally cup-shaped  -,  oscula  on  inner  side  of  cup  or  on  upper  flat  surface ; 
very  soft  and  elastic. 

E,  officinalis,  variety  rotunda.  Usually  massive;  attached  by  a 
broad  base ;  sides  vertical ;  oscula  large  and  conspicuous  on  top,  or 
small  in  longitudinal  rows  on  the  sides.  In  the  young  this  variety  may 
have  a  conical  form  with  only  one  orifice,  but  later  it  has  several  oscula. 
Its  rotundity  of  form  increases  with  the  number  of  large  orifices,  but  in 
the  adult  stages  the  form  varies,  some  being  conical,  while  others  have 
the  top  divided  into  radiating  ridges. 

E,  officinalis,  variety  dura.  Irregular,  massive,  horizontally  ex- 
panded, with  conical  process  on  upper  surface. 

Genus  Sippospongia 

H.  equina.  Some  of  the  sponges  of  this  species  are  massive,  spheri- 
cal, and  attached  by  a  small  base ;  others  are  horizontally  expanded  or 
cake-shaped ;  some  have  a  depression  in  the  upper  surface  and  become 
cup-shaped. 

H,  equina,  variety  cerehriformis.  Massive,  circular,  cake-shaped, 
often  depressed  in  the  center,  producing  a  cup-shape,  attached  by  broad 
base ;  surface  broken  up  by  parallel  longitudinal  ridges  having  many 
tufts.  Cup-shaped  forms  predominate,  and  have  a  more  or  less  rough 
surface.     This  is  one  of  the  species  known  as  grass-sponges. 

a,  equina,  variety  meandriforniis,  the  velvet  sponge.  The  sur- 
face of  this  variety  has  a  protruding  flattened  cushion  of  fiber  which 
slightly  resembles  the  convolutions  of  the  brain-coral.  Sometimes  these 
cushions  are  extended  into  long  pencils.  The  oscula  are  large  and 
ragged  on  the  edges ;  the  shape  is  irregular.  The  average  size  is  seven 
to  eight  inches  in  diameter.     (Plate  XL.) 

H,  equina,  variety  elastica  (variety  agaricina^,  Hyatt),  the  yellow 
sponge.  This  is  the  second  grade  of  commercial  sponge,  corresponding 
to  the  Zimocca  sponge  of  the  Mediterranean.  It  is  found  growing  with 
the  ^'  sheepswool"  in  a  depth  of  two  to  twenty  feet,  and  is  abundant. 
It  is  massive  and  cake-shaped.  The  whole  surface  is  a  network  covered 
with  numerous  small,  fine  cones.     (Plate  XL.) 

The  variety  dura  is  classed  with  this  species,  which  it  resembles  in 
appearance,  though  it  is  harder  in  texture. 

H,  canaliculafa.  Massive,  frondose ;  more  or  less  horizontally 
expanded ;  bears  finger-like  processes  of  varying  development  on  the 
upper  surface. 

H,  canalictdata,  variety  gossypina,  the  sheepswool  sponge.  This  is 
the  highest  grade  of  the  commercial  bath-sponge.  It  is  called  "sheeps- 
wool "  because,  perhaps,  of  its  irregular  shaggy  surface.  It  is  covered 
with  tufts,  the  larger  oscula  occupying  the  intervening  depressions. 


PLATE   XL. 

Euspongia  officinalis,  var.  adriatica.  Hippospongia  equina,  var.  meandriformis. 

Hippospongia  canaliculata,  Hippospongia  equina,  var.  elastlca. 

var.  gossyplna.  Euspongia  officinalis. 


SPONGES  109 

Sometimes  these  are  very  numerous,  the  whole  interior  being  cavernous ; 
again,  the  structure  is  more  dense,  with  fewer  large  openings  and  more 
of  the  small  ones  between  the  tufts ;  again,  the  depressions  are 
filled  up  so  that  the  surface  has  fewer  tufts.  When  living,  the  color  is 
shining  black.  This  is  the  best  sponge  found  on  the  American  coast, 
and  although  of  coarser  texture  than  the  best  Mediterranean  sponges,  it 
is  more  durable  and  quite  as  elastic.     (Plate  XL. ) 

JET.  canaliciilata,  yarietj  ficibelluni  {Spongia  gratninea,  Hyatt). 
This  is  one  of  the  species  of  sponges  of  the  third  commercial  grade, 
which  bear  the  trade-name  of  ^'  grass-sponge."  The  shape  is  cone-Hke, 
with  either  a  flat  or  a  funnel-shaped  top.  The  oscula  re  on  the  upper 
surface.  The  sides  are  fluted  with  deep  furrows  which  contain  the  small 
incurrent  apertures. 

Genus  Hircinia 

H.  campana.  The  normal  variety  is  vase-shaped,  but  the  species 
varies  greatly  in  form.  Some  varieties  have  branches.  When  living, 
its  color  is  black.  It  is  found  at  Key  West  in  four  to  forty  feet  depth. 
(Plate  XXXVIII.) 


II 

COELENTERATA 
(POLYPS) 


Phylum 

CCELENTERATA 

Classes 
HYDROZOA 

(Zoophytes,  small  Jellyfishes,  and  a  few  Corals) 

SCYPHOZOA 

(Large  Jellyfishes) 

ACTINOZOA 

(Sea-anemones  and  m,ost  of  the  Stony  Corals) 

CTENOPHORA 

(Comb-jellies) 


112 


CCELENTERATA 

THE  animals  inclnded  in  the  phylum  Coelenterata  were  once  all 
called  zoophytes,  or  animal  plants,  because  of  their  resem- 
blance to  vegetable  forms.  The  name  Coelenterata  is  derived 
from  two  Greek  words  meaning  "  hollow ''  and  "  intestine/'  and 
it  describes  the  anatomical  structure  of  each  member  of  the 
group.  They  are  commonly  known  as  polyps.  In  the  simplest 
forms  the  parts  which  perform  the  different  functions  cannot  be 
distinguished  one  from  the  other,  and  even  in  higher  forms  there 
is  but  little  differentiation.  Shakspere's  description  of  old  age 
apphes  to  them :  "  Sans  teeth,  sans  ej^es,  sans  taste,  sans  every- 
thing." 

Nevertheless,  this  very  low  order  of  animals  has,  like  the 
higher  orders,  such  a  diversity  of  form  and  habit  as  to  require 
classification.  Some  of  them  are  stationary,  and  of  these  some 
branch  like  plants ;  some  move  about  by  the  aid  of  tentacles,  some 
move  by  means  of  vibrating  cilia,  and  others  move  by  the  con- 
traction and  expansion  of  the  soft  body. 

Cuvier  included  them  in  his  Radiata,  a  class  comprising  all  the 
animals  whose  parts  diverge  or  radiate  from  a  central  axis. 
Recent  classification  has  divided  the  radiate  animals  into  several 
classes.  This  arrangement  of  parts  is  obviously  quite  different 
from  that  of  bilateral  symmetry,  or  the  disposal  of  parts  on  each 
side  of  a  longitudinal  axis.  The  type  of  radiate  structure  is 
shown  in  polyps.  The  body  is  a  sac,  in  the  center  of  which  is 
another  sac  or  axis.  This  is  the  digestive  cavity.  Vertical 
partitions  extend  from  the  central  to  the  outer  sac,  forming  dis- 
8  113 


114 


MARINE  INVERTEBRATES 


Diagram  of  radiate  structure. 


tinct  divisions  or  chambers.  The  number  of  divisions  varies 
with  the  different  species  and  also  with  the  age  of  the  animal. 
Other  partitions  start  from  the  outer  sac,  and  extend  toward  the 
central  axis,  but  do  not  unite  with  it.  These  partitions,  called 
mesenteries,  are  always  in  definite  multiples,  varying  in  different 
species,  new  divisions  growing  between  the  first  partitions  in 

regular  order.  On  the  inner  edge  of  these 
partitions  the  eggs  of  the  animal  are 
formed,  which,  when  mature,  drop  into 
the  chambers  and  pass  through  openings 
into  the  inner  sac,  or  digestive  cavity,  and 
out  of  the  mouth  into  the  water. 

The  animals  are  classed  according  as  the 
eggs  are  formed  on  all  or  on  special  par- 
titions, those  being  of  the  highest  order 
where  a  limitation  and  constancy  of  func- 
tion is  maintained.  The  upper  surface 
of  the  body  has  hollow  tentacles,  each  one  of  which  opens  into 
one  of  the  chambers  and  extends  outward.  All  parts  of  the 
animal  communicate,  and  whatever  enters  the  mouth  circulates 
through  the  whole  structure;  and  when  assimilation  is  com- 
pleted the  residue  returns  by  the  same  road  and  is  expelled 
through  the  mouth.  This  structure  is  common  to  all  polyps; 
but  there  are  great  differences  in  their  texture,  some  being  soft 
and  some  horny,  while  others  deposit  a  calcareous  skeleton 
(corals).  Some  grow  in  colonies,  like  the  hydroids  and  corals, 
and  are  stationary,  others  are  free  and  independent ;  some  have 
but  few,  others  have  many  tentacles ;  and  they  differ  widely  in 
size,  form,  and  color. 

Hydroids,  sea-anemones,  corals,  sea-fans,  starfishes,  and  sea- 
urchins  are  different  examples  of  the  radiate  structure.  They  are 
not,  however,  all  of  them  polyps. 

The  Cmlenterata  are  divided  into  four  classes :  Hydrozoa,  which 
include  the  colonies  of  zoophytes  which  resemble  seaweeds,  the 
small  jellyfishes  which  are  born  of  these  colonies,  and  the  mille- 
pores,  which  are  colonies  of  zoophytes  which  secrete  a  stony 
instead  of  a  horny  skeleton^  yet  differ  in  some  respects  from  other 


CCELENTERATA  115 

stony  corals ;  Scyphozoa,  large  jellyfishes,  many  of  wliicli  do  not 
have  the  double  form  of  development ;  Actinozoa,  the  sea-anemones 
and  the  different  forms  of  stony  corals,  including  sea-fans,  sea- 
pens,  etc. ;  Ctenophora,  the  jelly  fishes  commonly  known  as  comb- 
jellies. 


TABLE   SHOWING  THE  CLASSIFICATION  OF  THE  HYDROZOA 
DESCRIBED  IN  THIS  CHAPTER 

Class 
HYDROZOA 


Order  LEPTOLINLffi 

(Branched  colonies  or  shrub-like  communities  of  hydroids ;  some  permanently  fixed, 
others  liberate  swimmirig -bells) 


Suborders 


ANTHOMEDTJS^ 

(Zooids  not  covered  by 
protective  sheath  ;  um- 
brella of  medtisce  strong- 
ly arched;  egg-sacs  in 
manubrium) 


LEPTOMEDUSJE 

(Zooids  covered  ivith  cup- 
Uke  sheaths ;  umbrella 
of  medusce  thin  and  not 
very  convex  ;  egg-sacs  in 
line  of  radial  canals) 


TUBULARIANS 
(Without  polyp-cups) 


Divisions  Grenera  and  Species 

Clava  leptostyla 
Hydractinia  poly  din  a 
Coryne  mirdbilis 
Sarsia 

Eudendrium  ramosum 
Tubularia  indivisa 
T,  Couthouyi 
IParypha  crocea 
Corymorpha  pendula 
Hyhocodon  prolifer 
JPennaria  tiarella 
P,  gibbosa 
Sougainvillea  superciliaris 

/  Obelia  commissuralis 

I  Eiicope  dia2)7iana 

<J  Oceania  languida 

I  Clytia  poterium 
C,  bicophora 

r  Sertularia  piimila 

j  S,  argentea 

^  S,  cnpressina 

j  Aglaophemia  struthioides 
I  JPlumulavia  falcata 


CAMPANULARIANS 

(Polyp-cups  stalked) 

SERTULARIANS 
(Polyp-cups  sessile) 

PLUMULARIANS 

(Polyp -cups  on  one  side 
of  branches  only) 


Family 
GERYONOPSIDJE 

Family 
JEQUOREIDiE 


Tima  formosa 


Zygodactyla  groenlandica 


116 


HYDROZOA 


117 


Trachynenia  digitale 


Order  TRACHYLDf^ 

(No  fixed  zoophyte  stage ;  alivays  free-sivimming  medusce) 
Suborders  Genera  and  Species 

TRACHYMEDUS^ 

(Tentacles  spring  from 
margin  of  umbrella; 
mamibrium  long ;  go- 
nads in  connection  with 
radial  canals) 

NARCOMEDUS^ 

(Tentacles  spring  from 
midivay  hetiueen  sum- 
mit and  margin  of 
umbrella ;  manubrium 
short ;  gonads  in  con- 
nection with  manu- 
brium) 

Order   HYDROCORALLINA 

(Skeleton  of  carbonate  of  lime) 

Millepora  alcicornis 


Order  SIPHONOPHORA 

(Pelagic  free-swimming  colonies  ;  exhibit  extreme  polymorphism  of  zooids) 

Nano^nia  cava 
JPhysalia  arethusa 
Vellela  limbosa 


TERMS    USED    IN    DESCRIBING    HYDROIDS 

Coenosarc  (^^  QOjnm.011  flesh ")  •"  The  fleshy  axis,  or  organized 
living  bond,  by  which  the  zooids  are  organically  united  to  one 
another.  It  consists  of  three  layers :  ectoderm,  endoderm,  and 
mesoderm. 

Ectoderm  ("ontside  skin"):  The  ontside  one  of  the  three  or- 
ganized layers  of  which  every  hydroid  is  composed. 

Endoderm  ("  inside  skin") :  The  innermost  layer. 

Gonangium  ("seed-vessel"):  The  external  horny  receptacle 
within  which  the  gonophores  are  developed. 

Gonophore  (''  seed-bearing  ") :  A  generative  zooid. 

Hydranth  ("water  flower  ") :  A  nutritive  zooid. 

HydrorMza  ("  water-root") :  The  part  of  the  colony  which  fixes 
it  to  other  bodies,  like  a  root. 

Hydrosoma  ("  water-body  ") :  The  entire  hydroid  colony. 

Hydrotheca  ("water-receptacle"):  The  cup-like,  horny  recep- 
tacle which  protects  the  hydranth. 

Mesoderm  ("middle  skin"):  A  layer  which  lies  between  the 
ectoderm  and  the  endoderm. 

Nematophore  ("thread-bearing") :  The  name  of  peculiar  bodies 
developed  in  certain  genera  from  definite  points  j  characteristic 
of  plumularians. 

Perisarc  ("  around  flesh") :  The  transparent,  chitinous  shell,  or 
unorganized  outer  membrane  of  horny  consistency,  which  covers 
to  a  greater  or  less  extent  the  soft  parts  of  the  colony. 

Zooid  ("animal  form") :  One  of  the  animals  which  form  the 
colony. 


118 


CLASS  HYDROZOA 

SEAWEED-LIKE  ZOOPHYTES  AND   SMALL  JELLYFISHES 

THE  hydroids  have  been  called  the  nurses  of  jellyfishes.  From 
casual  observation  these  two  forms  would  not  be  associated 
together,  for  the  shrub-like  organisms,  which  so  much  resemble 
plants  that  they  are  often  collected  and  preserved  as  seaweeds, 
suggest  only  vegetable  life.  Examined  with  a  glass,  however, 
they  disclose  their  animal  nature.  Along  the  stems,  arranged  in 
various  ways,  are  small  cups,  from  which  protrude  the  numerous 
moving  tentacles  of  the  little  polyps  living  within  them. 

Hydroids  are  colonies  of  associated  animals  living  a  conimunal 
life.  The  multitude  of  individuals  composing  the  colony  are 
invested  with  a  horny  covering,  the  perisarc,  which  in  some  genera 
assumes  a  tree-hke  form.  Through  these  stems  and  branches 
runs  a  fleshy  tube,  a  thread  of  animal  substance,  which  connects 
in  one  living  whole  the  zooids,  or  individuals  of  the  community. 
There  is  division  of  labor,  as  in  other  communities :  some  of  the 
zooids  obtain  the  food  for  the  colony,  and  have  tentacles  around 
their  open  mouths  j  others  have  no  mouths,  but  reproduce  the 
species,  and  at  certain  stages  of  development  liberate  swimming- 
bells,  or  small  jellyfishes  (medusa?). 

The  typical  hydroid  colony  is  attached  by  a  kind  of  creeping 
stem  from  which  arises  a  vertical  axis,  which  gives  off  short 
lateral,  alternate  branches  bearing  zooids  at  their  ends.  There 
is  often  more  complex  branching.  The  zooids  in  certain  genera 
(tubularians)  are  uncovered;  in  others  (sertularians)  they  are 
incased  in  a  glassy,  cup-like,  horny  sheath. 

Three  kinds  of  zooids,  polyps,  or  hydranths— as  they  are  indis- 
criminately called— are  attached  to  the  stem.     Those  having  an 

119 


120  MARINE  INVERTEBRATES 

open  end  and  a  crown  of  tentacles  are  the  nutritive  individuals. 
Small,  club-like  dilations  are  immature  zooids.  The  hiastostyles, 
or  reproductive  zooids,  are  long,  cylindrical,  mouthless,  and  cov- 
ered. At  maturity  the  cover  is  ruptured,  and  the  medusge  have 
the  appearance  of  a  pile  of  thin  saucers  attached  by  the  middle 
of  the  convex  side.  When  at  length  these  saucers  are  set  free 
as  little  medusae,  or  jelly  fishes,  the  convex  side  of  each  saucer,  or 
swimming-bell,  is  called  the  ex-umdrella  ;  the  concave,  under  side, 
the  siibmnhrella.  From  the  center  of  the  subumbrella  projects 
the  manubrkmij  or  stomach  of  the  animal.  At  the  free  end  of  the 
manubrium  is  a  four-cornered  mouth.  From  the  attached  end 
of  the  manubrium  four  tubes  or  canals  diverge,  and,  extend- 
ing through  the  animal,  open  into  a  circular  canal  which  runs 
around  the  margin  of  the  umbrella.  When  the  medusa  is  as 
above  described,  it  has  reached  the  highest  point  in  its 
development. 

When  the  medusa  has  matured,  it  lays  eggs,  known  as  planulce. 
These  are  spherical  bodies  covered  with  cilia  (hairs),  by  means  of 
which  they  swim  about  for  a  time ;  but  they  finally  attach  them- 
selves to  some  object,  there  to  grow  and  develop  into  hydroid 
colonies.  The  cycle  of  life  is  thus  completed.  This  process  is 
known  as  alternation  of  geMeration,  or  metagenesis,  one  life-history 
containing  two  quite  different  forms  of  being.  The  term  of  life 
of  an  individual  is  one  year,  the  zoophyte  stage  beginning  in  the 
autumn  and  the  medusa  stage  in  the  spring. 

Some  medusse,  besides  reproducing  by  means  of  eggs,  multiply 
by  budding,  small  medusee  growing  on  the  manubrium  or  on  the 
margin  of  the  umbrella.  Sarsia  and  Lizzia  sometimes  increase 
by  budding. 

The  Hydrozoa  are  not  all  of  the  above  type.  In  the  sertularians 
the  zooids  perish  on  the  stem  and  have  no  medusa  life,  their 
reproductive  element  giving  rise  to  the  hydroid  form  without 
metamorphosis.  The  Trachijlince  have  no  hydroid  life,  being 
always  free-swimming  medusse;  others,  the  Siplionophora,  live  a 
hydroid  life  which  is  unattached,  the  colony  floating  on  the  ocean  ; 
the  millepores  secrete  calcareous  skeletons  and  always  remain 
fixed,  reproducing  by  budding. 


HYDROZOA  121 

Hydroids  are  very  abundant,  but  are  comprised  in  the  few 
groups  mentioned :  namely,  those  which  live  only  in  the  fixed 
colonial  state;  those  which  have  alternation  of  generation,  being 
first  hydroids  and  then  swimming-bells,  or  medusae;  those 
which  live  always  in  the  medusa  state,  the  eggs  of  the  jellyfish 
developing  at  once  into  other  medusae ;  and  the  ^iplionopliora,  or 
those  which  have  a  floating  colonial  state,  the  hydroid  never  being 
attached,  but  floating  at  large  and  capable  of  locomotion,  some  of 
the  colony  having  the  function  of  propulsion. 

Hydroids  are  particularly  interesting  as  exemplifying  the  close 
resemblance  that  may  exist  in  outward  appearance  between  ani- 
mal and  vegetable  life  and  as  illustrations  of  communal  life  and 
of  the  alternation  of  generation,  A  few  examples  of  different 
types  are  given  below. 

.ORDER  LEPTOLINI^ 

The  members  of  this  order  agree  in  all  essential  particulars 
being  branched  colonies  having  two  principal  forms  of  zooids, 
the  nutritive  and  the  reproductive.  Some  genera  attain  the 
length  of  several  inches,  or  even  feet ;  others  are  very  small  tufts 
growing  on  shells  and  seaweeds.  The  cup  may  completely  in- 
close the  zooid  and  be  close  to  the  stem  (sessile),  as  in  sertula- 
rians ;  it  may  be  on  the  end  of  a  short  stalk,  as  in  campanula- 
rians ;  or  it  may  not  reach  above  the  base  of  the  zooid,  as  in 
tubularians.  The  genera  are  based  upon  these  differences  in  the 
perisarc. 

The  hydroids,  like  all  other  classes,  exist  in  such  great  variety 
that  it  would  be  impracticable  to  describe  here  the  many  named 
species ;  but  to  recognize  the  genera  is  simple.  A  long  tubular 
pedicel  without  a  cup  is  characteristic  of  the  tubularians ;  the  cam- 
panularians  have  an  arborescent  form  and  bell-shaped  cups  on 
stalks ;  the  sertularians  have  sessile  cups ;  and  the  plumularians 
have  a  feather-like  form,  with  zooid-cups  on  one  side  only  of  the 
branches. 

The  beautiful  and  varied  structure  of  these  ^^  animal  plants  "  is 
most  interesting,  and  to  be  fully  appreciated  they  should  be  seen 


122  MARINE  INVERTEBRATES 

in  life  aiid  examined  with  a  glass.  Some  species  are  confined  to 
deep  water,  but  many  are  littoral  and  to  be  found  in  tide-pools, 
in  the  chinks  and  crannies  of  rocks,  under  stones,  and  under  the 
hanging  Fuciis.  The  horny  skeletons  of  large  varieties  are  fre- 
quently washed  ashore,  and  in  theii*  tangled  masses  smaller 
living  species  often  may  be  found. 

THE  TUBULARIANS 

This  division  is  characterized  by  zooids  borne  on  long,  slender 
stems  which  are  sometimes  simple  and  small,  sometimes  branch- 
ing and  eight  to  ten  inches  long.  The  zooid  has  two  rows  of 
tentacles,  the  central  one  being  sometimes  on  a  kind  of  probos- 
cis. The  reproductive  zooids  are  in  bunches,  sometimes  below 
the  outer  row  of  tentacles,  sometimes  between  the  two  rows. 
The  perisarc  does  not  cover  the  zooid.  In  color  they  are  com- 
monly red  or  yellow. 

Genus  Clava 

C,  leptostyla.  This  species  is  found  growing  on  Fucus,  on  the  under 
side  of  stones  at  low- water  mark,  and  in  tide-pools,  where  it  often  covers 
several  feet  of  the  surface  of  the  rock  with  a  dehcate  velvet-like  carpet. 
It  is  red  in  color  and  is,  apparently,  a  soft  and  tender  species,  but  it 
thrives  on  the  most  exposed  beaches.  The  colonies  are  cylindrical  tubes 
about  one  quarter  of  an  inch  in  height,  rising  from  a  creeping  stem 
{hydrorhiza).  Each  tube  is  surmounted  by  a  zooid  with  fifteen  to  thirty 
tentacles,  which  is  constantly  changing  form  by  its  contractions.  Below 
the  tentacles  are  reproductive  buds  arranged  in  clusters.  Common  from 
Long  Island  Sound  northward.     (Plate  XLI.) 

Genus  My cir actinia 

jff.  polyclina.  The  soft,  pinkish  covering  often  seen  on  shells  inhab- 
ited by  hermit-crabs.  This  association  of  two  different  kinds  of  animals 
is  known  as  commensalism,  and  is  a  partnership  formed  for  the  benefit  of 
one  or  both  the  individuals.  In  this  case  the  mossy  appearance  of  the 
hydroid  conceals  the  shell,  while  the  stinging-cells  with  which  it  is  in- 
vested are  weapons  of  defense  against  the  enemies  of  the  crab  and  also 
help  to  paralyze  its  prey.  In  return  for  these  favors  the  colony  is 
moved  about,  thereby  obtaining  perhaps  better  oxygenation.  Originally 
it  was  thought  that  Hydractinia  lived  only  on  the  shells  occupied  by- 
hermit-crabs,  and  that  the  nomadic  life  was  essential  to  its  existence  :  but 
this  is  not  the  case,  for  it  is  also  found  growing  on  rocks  in  tide-pools. 
These  colonies  arise  from  a  creeping  stem,  wMch  forms  a  horny,  root- 


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PLATE   XLI. 


Clava  leptostyla. 
Tubularia  indivisa. 
Hybocodon  prolifer. 


Coryne  mirabilis. 
EudendriuTii  ramosum. 
Tubularia  Couthouvi. 


HYDROZOA 


123 


like  network  over  a  surface  and  develops  at  intervals 
projecting  points  on  which  the  zooids  live.  Each 
colony  consists  of  feeding  members^  of  reproductive 
members,  and  of  a  third  kind  which  seems  to  have 
a  protective  function.  These  last  are  more  slender 
than  the  others,  and  are  without  tentacles,  but  are 
armed  with  lasso-  or  stinging-cells.  The  colonies  are 
of  different  sexes,  the  male  being  lighter  in  color  than 
the  female  colonies.  The  eggs  develop  into  planulae, 
which  swim  about  for  a  while  and  then  give  rise  to 
other  colonies.  It  is  found  from  New  Jersey  north- 
ward, and  is  very  abundant  in  Long  Island   Sound. 

Genus  Coryne 

C,  tnirabilis,  A  hydroid  about  one  inch  high,  growing  in  patches 
and  appearing  like  tufts  of  moss  on  rocks  between  tide-marks.  When 
highly  magnified  it  shows  club-shaped  tubes  with  pedicels,  terminating 
in  zooids,  scattered  over  the  swollen  ends.  The  medusa-bud  is  larger 
than  the  others  and  is  lower  on  the  tube.  It  liberates  a  swimming-bell, 
which  is  called  Sarsia.     (Plate  XLI.) 


Colony  of  Coryne, 
natural   size. 


Sarsia 

/S».  mirahilis.  This  medusa  of  Coryne  is  from  one 
quarter  to  three  quarters  of  an  inch  in  diameter  when 
fuU-grown.  Its  umbrella  is  nearly  hemispherical,  and 
from  the  center  hangs  a  manubrium.  From  the  margin 
of  the  umbrella  hang  four  very  long  tentacles.  The  shape 
of  its  body  and  the  length  of  its  tentacles  and  proboscis 
are  constantly  changing  as  it  moves  in  the  water.  These 
httle  medusae  are  very  plentiful  in  the  spring  and  summer, 
and  swim  rapidly  in  all  directions  near  the  sm-face  of 
the  water. 

Genus  Tuhularia 

T,  Couthouyi,  This  species  is  found  in  the  same  places 
as  Parypha  crocea.  The  stem  is  three  to  six  inches  long, 
and  is  inclosed  in  a  horny  sheath,  which  is  more  or  less 
ringed  or  jointed,  or  it  may  be  smooth  throughout.  The 
head,  when  the  tentacles  are  expanded,  measures  one  and 
a  half  inches  in  diameter.  It  has  a  proboscis  covered  with 
tentacles,  disposed  in  series,  which  grow  successively 
shorter,  the  last  being  merely  papillae.  The  medusa-buds 
hang  in  clusters  between  the  outer  tentacles  and  the  pro- 
boscis. The  animal  grows  in  bunches  of  five  to  ten  tubes, 
which  spring  from  a  creeping,  tangled  stem.    (Plate  XLI.) 

Genus  I^arypha 

Sarsia,  the  free        ^»  cvocea.    This  is  One  of  the  most  beautiful  of  the  tubu- 
medusa  of  Coryne.  lariaus.    It  has  a  large,  drooping  head  on  a  stem  three  to 


124 


MARINE   INVERTEBRATES 


four  inclies  long.  It  is  bright  red  in  color,  and  from  the  center  of  the 
circle  of  tentacles  the  reproductive  zooids  hang  in  a  cluster,  like  a  bunch 
of  grapes.     It  does  not  liberate  swimming-bells.     It  is  found  in  bunches 

on  piles  of  wharves  and  bridges,  in  brack- 
^'1  ish  water,  on  the  eastern  coast  as  far 

south  as  Charleston,  South  Carolina. 


Corymorpha  pendula, 

XLII. 


See  Plate 


Genus  Hyhocodon 

H.  proUfer,  One  of  the  largest 
tubularians,  somewhat  resembling  Pa- 
ryplia  crocea.  It  is  deep  orange  in  color, 
and  the  head  is  erect  on  a  long 
stem.  The  reproductive  zooids  are  in 
a  cluster  in  the  center  of  a  double  row 
of  tentacles,  and  resemble  a  basket  of 
fruit.  It  grows  singly,  or  in  groups  of 
two  or  three,  in  shaded  tide-pools,  which 
are  protected  from  the  surf,  and  in  which 
the  water  is  very  pure.  It  is  found  on 
the  Massachusetts  coast,  but  is  not 
common.  This  species  Hberates  swim- 
ming-bells.    (Plate  XLL) 

GrENus  Fennaria 

P,  tiarella.     The  branches  are  ar- 
ranged alternately  and  at  right  angles 
to  a  central  stem  or  axisj  they  taper, 
being  shortest  at  the  top  and  bottom  of 
„_^.  the  stem.     The  zooids  are  red  in  color, 

and  are  arranged  along  the  upper  side 
of  branches  at  considerable  intervals.  The  stems  are  black  and  beaded, 
being  constricted  at  intervals.  The  zooids  have  two  rows  of  tentacles, 
the  upper  ones  on  a  small  proboscis.  From  the  lower  part  of  the  pro- 
boscis deep,  beU-shaped  bodies,  which  eventually  become  swimming- 
bells,  are  developed.  The  species  is  found  on  rocks  and  eel-gTass  along 
the  whole  eastern  coast. 

P,  gibhosa.  A  species  similar  to  P.  tiarella,  found  on  the  coast  of 
Florida. 

Genus  Boiigainvillea 

B.  super ciliaris.  This  hydroid  is  found  in  tide-pools  on  the  New 
England  coast,  growing  in  clusters,  about  two  inches  high,  attached  to 
rocks  or  to  mussel-shells.  The  stem  is  very  slender,  and  branches.  It  is 
red  in  color.  The  medusae  which  it  liberates  are  found  in  great  numbers 
in  the  spring.  The  tiny  swimming-bells  are  nearly  globular.  The  tenta- 
cles are  long,  are  arranged  in  four  clusters  on  the  margin,  and  extend  in 
every  direction.  The  manubrium  is  yellow  and  short,  and  the  mouth  is 
concealed  by  four  clusters  of  short  tentacles.     On  these  oral  tentacles 


Pennaria  tiarella ;  a  branch,  natural 


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PLATE   XLII. 

Corymorplia  pendula. 
Clytia  bicophora. 


■i  >■ 


PLATE   XLII,  A. 

Obelia  longissima. 
Clytia  poterium.  Sertularia  pumila. 


HYDROZOA  125 

the  eggs  of  tlie  animal  are  produced.    In  its  habits  it  is  sluggish ,  often 
remaining  in  one  position  for  several  days. 


THE    CAI^IPANULARIANS 

The  hydroids  which  have  an  open,  bell-shaped  cup  at  the  ter- 
mination of  a  short,  stalk-like  stem,  or  branchlet,  are  mostly 
campanularians.  This  division  embraces  jellyfishes  of  different 
families.  Many  medusae  cannot  be  referred  with  certainty  to 
the  hydroids  from  which  they  sprang,  and  the  medusa-buds  of 
many  of  the  hydroids  have  not  been  noted. 

Genus  Obelia  (Plate  XLII,  A) 

O.  coniinissuralis.  This  is  a  delicate,  much-branched  hydroid,  five 
to  six  inches  long,  found  at  low-water  mark  in  tide-pools,  attached  to 
stones  and  seaweeds,  along  the  rocky  shores  from  Nova  Scotia  to  South 
Carolina.  Its  branches  are  arranged  spirally  and  spread  nearly  at  right 
angles  to  the  main  stem,  and  the  main  branches  subdivide  in  a  simGar 
manner.  Every  interval  of  the  stem  has  a  slight  curve,  and  at  the  base 
of  every  branch  there  are  four  or  five  rings.  The  ultimate  branches,  or 
pedicels,  bear  at  their  ends  bell-shaped  cups  which  have  even  edges, 
but  are  twelve-sided  and  slightly  incurved.  The  pedicels  are  ringed  for 
the  whole  length.  The  reproductive  cups  on  short  ringed  pedicels  are 
larger  than  the  others,  and  occupy  the  angles  of  the  branches.  These 
cups  are  constricted  and  again  expanded  at  the  apex,  forming  an  urn- 
like top. 

Genus  JEiicope 

E,  diaphana.  This  species  is  often  abundant  on  the  fronds  of  Lami- 
naria  washed  ashore,  and  also  on  Bhodymenia  and  Fucus.  It  has  a 
creeping  base,  zigzag  in  form,  but  keeping  a  straight  course,  and  in  its 
branching  often  forming  a  network  over  the  surface  of  the  flat  fronds. 
At  each  angle  of  the  creeping  stems  rises  a  pedicel  about  an  inch  high, 
which  inclines  in  the  direction  of  the  stem  and  terminates  in  a  zooid-cup 
similar  in  form  to  that  of  Obelia.  The  medusa  which  this  hydroid  liber- 
ates is  called  Thaumatias  diaphana.  The  swimming-bell  is  very  shallow 
and  thin,  turning  inside  out  at  almost  every  pulsation.  The  "tentacles 
are  numerous  and  rigid  like  stiff  hairs.  This  little  medusa  is  very  active 
and  is  abundant.  The  species  is  found  from  Long  Island  Sound  north- 
ward. 

Genus  Oceania 

O,  languida.  This  medusa  is  one  inch  in  diameter  and  one  half  of 
an  inch  high,  and  is  so  delicate  and  transparent  that  it  is  hardly  visible 
except  in  its  outlines.  In  its  early  stages  it  is  nearly  spherical  and  has 
no  tentacles ;  later  the  disk  flattens  and  has  from  thirty-two  to  thirty- 


126  MARINE  INVERTEBRATES 

six  tentacles  and  numerous  eye-spots.  When  disturbed  it  flattens  its 
disk  and  folds  together,  leaving  its  tentacles  sprawled  in  every  direction. 
It  is  very  languid  in  its  movements,  and  often  remains  in  one  position 
for  hours.  These  medusae  are  found  only  in  the  hottest  hours  of  the 
day,  but  are  very  plentiful  then,  shoals  of  them  often  stretching  for 
miles,  and  so  thick  as  to  touch  one  another.  Their  habitat  is  the  New 
England  coast. 

Genus  Clytia 

C,  poterium.  This  hydroid  is  found  creeping  over  seaweeds  in  tide- 
pools  from  Long  Island  Sound  northward.  The  main  stem  is  prostrate, 
or  root-like,  running  over  the  body  to  which  it  is  attached.  The  stems 
rise  as  do  the  tubularians.  The  sterile  zooids  are  on  single  stems  about 
one  quarter  of  an  inch  high.  The  stems  are  faintly  ringed  for  their 
entire  length,  and  at  the  top  have  a  distinct  ring,  on  which  rests  an  open, 
bell-shaped  cup,  which  is  smooth  around  the  rim.  The  reproductive 
zooids  are  on  very  short  pedicels,  and  the  cups  are  long  and  cylindrical, 
with  a  wavy  outline.     (Plate  XLII,  A.) 

C.  bicophora.  This  species  is  found  in  the  same  places  as  the  pre- 
ceding, and  is  of  about  the  same  size.  The  long  stems  are  more  or  less 
ringed  and  sometimes  branched.  The  edges  of  the  cups  are  notched. 
The  medusa-buds  are  urn-shaped  and  ringed,  and  are  on  very  short 
pedicels.     (Plate  XLII.) 

THE   SERTULARIANS 

The  sertularians  are  distinguished  by  the  horny  cup,  which  is 
sessile— that  is,  set  directly  against  the  stem  instead  of  being 
raised  upon  a  stalk.  They  are  among  the  most  common  objects 
of  the  beach,  and,  like  the  plumularians,  are  often  mistaken  for 
plants  by  the  amateur  collector  and  are  gathered  and  pressed  as 
seaweeds.  They  are  found  everywhere  along  the  coast.  They 
zigzag  over  the  fronds  of  seaweeds  or  hang  in  fringes  upon  them, 
as  well  as  upon  rocks,  stones,  and  shells.  They  well  repay  close 
examination  with  a  glass.  Every  open  cup  bears  a  wreath  of 
tentacles,  which  makes  the  branch  a  spray  of  stars.  This  is  not 
an  inappropriate  comparison,  for  besides  their  starry  shape  some 
species  emit  a  phosphorescent  light. 

Genus  Sertularia 

S,  pumila.  The  most  abundant  of  all  the  hydroids  on  the  northeast 
coast  is  this  species,  which  is  found  in  profusion  upon  Fucus  and  other 
seaweeds,  and  mingled  with  them  upon  the  rocks.  It  is  easily  distin- 
guished from  the  campanularians  because  its  zooid-cups  are  close  against 
the  stems  (sessile)  instead  of  on  stalks  or  pedicels.     The  stem  creeps 


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PLATE  XLIII. 


Plumularian  hydroid. 

Aglaophemia  struthioides,  magBifled. 


Aglaophemia  struthioides. 
Plumularia  falcata. 


HYDEOZOA  127 

over  the  fronds  of  seaweeds,  often  crossing  and  recrossing  in  a  tangled 
mass.  At  short  intervals  the  upright,  straight  branches  rise  to  one  inch 
or  one  and  a  half  inches  in  height,  and  arc  more  or  less  branched.  All 
except  the  creeping  stems  are  close  set  on  each  side,  with  cylindrical 
zooid-cups  which  turn  outward  at  the  ends.  The  cups  of  the  reproduc- 
tive zooids  are  not  sessile  -,  they  are  much  larger  than  those  of  the  nutri- 
tive ones  and  are  urn-shaped.     (Plate  XLII,  A.) 

S,  argentea.  This  is  a  beautiful  species,  common  from  New  Jersey 
northward.  It  has  a  profusion  of  silvery  branches  on  a  dark  stem.  The 
colonies  are  often  a  foot  or  more  long,  and  the  branches  at  the  top  and 
bottom  of  the  stem  are  shorter  and  fewer  than  those  in  the  middle  of 
the  colony.  The  zooid-cups  are  nearly  cylindrical,  pressed  closely  to  the 
stem,  nearly  opposite  or  subalternate  to  one  another,  and  end  in 
pointed  tips.  The  medusa-bud  is  urn-shaped,  with  two  horns  at  the  top. 
(Plate  XLII,  B.) 

S.  ciipressina,  the  sea-cypress.  This  species  is  similar  to  S.  argentea, 
but  the  main  stem  is  thicker  and  longer,  and  the  branches  less  crowded 
and  less  subdivided.  The  branches  are  arched  or  drooping,  instead  of 
straight,  and  gradually  decrease  in  length  at  some  distance  from  the 
lower  and  upper  parts  of  the  stem,  giving  a  spire-like  apex,  the  stem 
often  continuing  into  a  bare,  branchless  extremity.  The  zooid-cups  are 
tubular,"  not  much  narrowed  or  divergent  above,  and  two-lipped  on  the 
margin.     It  is  found  from  New  Jersey  northward.     (Plate  XLII,  B.) 

THE    PLUMULARIANS 

These  hydroids  are  feather-like  in  the  manner  of  branching, 
short  lateral  branches  being  arranged  on  each  side  of  a  long  cen- 
tral stem.  In  some  species  the  stems  are  naked  below  and 
resemble  quills.  The  zooid-cups  are  only  on  one  side  of  the 
short  branches.     (Plate  XLIIL) 

GrENUs  Aglaophemia 

A,  struthioides,  the  ostrich-plume.  This  species,  which  is  found  on 
the  Pacific  coast,  is  perhaps  the  most  beautiful  of  the  hydroids.  It  varies 
in  size  and  color,  but  always  suggests  a  small  ostrich-plume.  The  zooid- 
caps  are  arranged  in  a  single  row  on  one  side  of  each  short  branch,  and 
the  main  stem  has  a  joint  between  each  of  the  branches,  which  are 
placed  quite  close  together.  The  rims  of  the  cups  have  sharp -pointed 
teeth,  and  from  the  top  emerge  three  tubular  projections,  which  are 
called  nematophores,  and  are  supposed  to  be  degenerate  zooids.  At  inter- 
vals a  branch  is  replaced  by  a  cylindrical  body  covered  with  nemato- 
phores, and  in  these  the  generative  zooids  are  developed.     (Plate  XLIII.) 

Genus  TluTnularici 

P.falcata  (Johnston),  or  Hydrallmania  falcata  (Hincks).  This 
species  is  found  on  shells  and  rocks  near  low-water  mark  from  Long 


128 


MARINE  INVERTEBRATES 


Island  Sound  northward.  It  is  from  four  to  twelve  inehes  high.  The 
main  stem  is  in  long  spiral  turns,  and  at  intervals  has  spreading  plumose 
branches.  The  zooid-cups  are  tubular  and  closely  pressed  against  one 
another,  and  are  ranged  in  rows  on  one  side  of  the  branchlets ;  the  aper- 
tures of  the  cups  are  plain  and  oblique.     (Plate  XLIII.) 


Family  geryonopsid^ 

Genus  Tima 

T.  formosa,  A  very  delicate  and  transparent  medusa ;  size  one  to 
two  inches  in  diameter;  .beU  conical;  radial  tubes  four  in  number; 
manubrium  long,  hanging  far  below  the  disk ;  four  frilled  appendages 
diverging  from  the  corners  of  the  mouth ;  tentacles  thirty- two ;  egg- 
sacs  white  and  following  the  line  of  the  radial  tubes  in  undulating  folds. 
This  species  is  not  very  common ;  it  is  found  on  the  New  England  coast. 


Family  ^quoreid^ 
Genus  Zygodactyla 


Zygodactyla  groenlandica. 


Z,  groenlandica.  Medusa 

seven  to  eleven  inches  in  diam- 
eter ;  disk  violet-colored  and 
transparent ;  margin  fringed  with 
long,  fine,  contractile  tentacles  of 
a  darker  violet  color ;  numerous 
radiating  tubes;  egg-sacs  in 
slightly  waved  plates ;  manubrium 
hanging  below  the  line  of  the  disk 
and  with  a  thin  frilled  membrane 
depending  from  it.  Found  north 
of  Cape  Cod  in  July. 


ORDER  TRACHYLINiE 

The  TraclnjmeduscB  are  characterized  by  their  direct  develop- 
ment, the  egg  of  the  jellyfish  producing  a  medusa  and  not  a 
hydroid  colony. 

Genus  Trachynema 

T,  digitale.  Size  one  inch  to  one  and  a  half  inches  in  height ;  rose- 
colored ;  the  bell  thin  and  hard,  and  conical  at  the  top.  The  swimming 
is  effected  by  contractions  of  the  muscular  velum  (the  band  around  the 
inner  margin  of  the  umbrella)  instead  of  wholly  by  the  bell.  The  ten- 
tacles are  long  and  numerous,  and  are  curled  up  when  moving.  The 
manubrium  is  long  and  has  four  expansions  at  the  mouth.     Eight  egg- 


HYDROZOA 


129 


cases  hang  in  long  pendent  sacs  from  the  upper  part  of  the  radial  canals 
and  reach  nearly  to  the  velum.  Four  garnet-colored  eyes  in  club-shaped 
processes  are  prominent  on  the 
margin.  The  animal  moves  by 
jerks  in  straight  lines. 

ORDER  HYDROCOEALIINA 

CALCAREOUS   HYDROIDS 

The  genus  Millepora  ("thou- 
sand pores  "),  which  is  the  type 
of  this  order,  is  a  colony  of 
animals,  like  other  hydroids, 
which  secrete  calcareous  in- 
stead of  horny  coverings.  It 
differs  from  true  corals  in  that 
the  members  of  a  colony 
perform  different  functions, 
whereas  in  true  corals  each 
member  of  a  community  is  a 
complete  individual.  It  differs 
algo  in  the  arrangement  of 
the  stony  partitions,  which  in 
Hydrocorallina  are  the  outside 

1  1  •  Trachynema  digitale. 

CO  verm  gs      and     connectmg 

canals,  but  in  true  corals  are  vertical  partitions  inside  the  animal, 

between  the  inner  and  outer  sacs,  as  explained  on  page  114. 

Genus  Millepora 

M,  alcicornis,  elk-horn  coral.  This  beautiful  coral,  which  is  abun- 
dant in  Florida  and  contributes  to  the  building  of  the  reefs,  rises  in 
broad  expansions,  more  or  less  lobed,  and  suggests  by  its  shape  the 
object  for  which  it  is  named.  The  whole  mass  is  porous,  being  traversed 
by  innumerable  canals.  Its  surface,  although  smooth  compared  with 
that  of  other  corals,  is  covered  with  very  minute  pores,  which  are  of  two 
sizes.  The  larger  ones  are  the  gastropores,  or  stomach-pores,  in  which  the 
nutritive  animal  lives ;  it  has  a  cylindrical  body,  with  four  knob-like 
tentacles  and  a  mouth.  Placed  more  or  less  irregularly  around  the 
gastropores  are  smaller  pores,  the  dactylopores  (finger-pores),  from  which 
emerge  slender  mouthless  processes,  or  dactylo^ooids,  with  tentacles  and 
stinging-cells.  These  seem  to  be  the  guard-polyps  of  the  community. 
The  cups  occupied  by  the  zooids  are  shallow.  As  one  animal  dies, 
another  succeeds  it  and  builds  a  horizontal  partition  separating  the 
new  cup  from  the  old  one.  Thus  the  stony  mass  increases  in  size  by 
the  progress  of  succeeding  generations  of  zooids.  The  living  animal 
occupies  only  the  outer,  open  space.  (Plate  XLIV.) 
9 


130 


MARINE  INVERTEBRATES 


ORDER  SIPHONOPHORA 


FREE-SWIienNG  COLONIES 


This  order  of  hydroids  consists  of  free-floating  communities 
and  is  one  of  peculiar  interest,  since  it  shows  in  a  clear  manner 
the  special  function  of  each  individual  member  of  the  colony, 
and  illustrates  better  than  the  foregoing,  perhaps,  the  curious 
forms  of  animal  life  which  this  class  presents. 

Genus  Nanomia 

N,  cava.  This  species  is  found  on  the  New  England  coast.  The 
members  of  the  community  are  arranged  along  a  hollow  stem  about  three 

inches  long  which  opens  into 
every  individual.  At  the  top 
of  the  stem  is  a  sac,  or  float ; 
just  below  this  is  a  group  of 
swimming-bells  which  have 
no  manubrium  or  mouth,  and 
whose  sole  function  is  to  pro- 
vide locomotion  for  the  com- 
munity ;  and  below  these  are 
three  sets  of  zooids,  each 
having  a  triangular  shield 
and  tentacles.  The  tentacles 
are  longer  than  the  main  stem. 
One  of  these  last  groups  con- 
sists of  the  nutritive  members, 
the  mouths  of  the  community, 
resembling  manubriums  of 
swimming-bells  out  of  place. 
Each  one  has  at  the  point  of 
attachment  a  bunch  of  long, 
delicate  tentacles  having  pen- 
dent knobs  of  lasso-ceUs.  A 
second  group,  also  with 
mouths,  has  shorter  tentacles 
which  are  carried  in  spiral 
coils.  The  members  of  the 
third  group  have  but  one  ten- 
tacle each  and  resemble  the 
float  at  the  end  of  the  stem ; 
presumably  these  drop  off  and 
produce  new  colonies.  There 
are  also  on  the  lower  part  of 
the  stem  other  reproductive 
members,  which  resemble  the 

A(hxit  Nanomia  cava.  clusters      of      buds     SCCU     On 


HYDROZOA 


131 


tubularian    hydroids.      These  animals  are  pink  in    color  and  move 
through  the  water  with  a  graceful  swaying  motion. 


Genus  JPhysalia 

jP.  arethiisa,  the  Portuguese  man-of-war.    This  colony  is  perhaps  the 
best-known  one  of  the  group,  since  it  attracts  much  attention  in  Southern 
waters,  and  is  also  one  of  the  most  remarkable  examples  of  an  animal 
community.      The    most    prominent    part 
of    the    compound  body   is  the    float,   an 
oblong  pear-shaped  bag,  full  of  air,  which 
floats  on  the    surface   of    the   water.     Its 
color  is  bright  blue,  varying  to  rose.     On 
the  upper  side  of  this  air-vessel  is  a  crest,  or 
sail,  and  from  the  under  side  depend  long 
tentacles,  or  streamers.     Some  of  these  ten- 
tacles are  covered  with  stinging-  or  lasso- 
cells  )  some  are  the  feeding  zooids,  with  flask- 
shaped  bodies,  and  some,  which  look  hke 
bunches  of   grapes,  are  the   reproductive 
zooids.    The  tentacles  in  this  curious  cluster 
are  all  close  together  and  hang  from  one 
side  of  the  float,  near  the  broader  end.     The 
longest  are  on  the   outside,  which  may  be 
called  the  windward  side,  since  they  serve  to 
keep  the  crest,  or  sail,  before  the  wind  ;  and 
when  the  wind  is  strong  they  stretch  out  to 
a  remarkable  length, —  forty  to  fifty  feet, — 
acting  as  anchors  to  keep  the  colony  from 
being  driven  ashore.     They  also  change  its 
course  by  raising  the  pointed  end  of  the 
float,  thus  forcing  it  to  "  come  about."    These 
long  tentacles,  ordinarily  carried  more  or  less 
curled  up,  are  in  bunches  of  two  to  four,  and 
emerge  from  a  common  stem.     Clusters  of 
similar,  but  smaller,  tentacles  alternate  with 
the  larger  ones,  but  grow  somewhat  nearer 
the  pointed  end  of  the  float ;  these  are  purely 
locomotive  organs.    Next  come  two  smaller 
sets  of  appendages,  also   of  unequal  size, 
which  are  the  nutritive  organs  of  the  com- 
munity.   They  are  clustered  together  on  a 
stem  like  the  others.     The  appendages  of 
the  third  kind  are  small,  resemble  bunches 
of  grapes,  and  are  scattered  among  the  nutritive  hydrae. 
are  the  reproductive  zooids  of  the  community. 


Physalia  arethusa,  Portuguese  man- 
of-war,  one  fifth  natural  size. 

These  last 


Genus  Vellela 

F.  limbosa.    This  hydroid  is  abundant  on  the  Florida  coast.    It  has 
a  bright-blue,  flattened,  oblong,  bladder-like  float,  four  to  five  inches 


X32 


MARINE  INVERTEBRATES 


long,  which  is  divided  into  a  number  of  concentric,  communicating  com- 
partments. The  margin  of  the  float  is  entire,  and  a  triangular  sail 
extends  diagonally  across  the  top.  On  the  under  side  is  a  single  mouth 
on  a  manubrium,  and  surrounding  it  are  a  large  number  of  short  thread- 
like appendages  having  different  functions.  Some  of  them  are  feelers, 
others  bear  reproductive  buds,  and  others  have  stinging- cells.  Associ- 
ated with  Vellela  is  an  allied  hydroid  called  Porpita,  which  has  no  sail, 
and  in  company  with  these  two  is  a  jellyfish  called  Bataria,  which  is 
supposed  to  be  the  offspring  of  one  or  the  other  of  them. 


Vellela  limbosa. 


TABLE    SHOWING    THE    CLASSIFICATION    OF    THE    SCYPHOZOA 
DESCRIBED  IN  THIS  CHAPTER 

Class 
SCYPHOZOA 

(Velum  usually  absent  and  tentaculocysts  ■present ,-  the  eggs  are  discharged  into  a 
gastric  cavity.    The  type  of  this  class  is  Aurelia) 


Orders 
STAUROMEDUSJE 

(Umbrella  conical  or 
vase-shaped;  no  ten- 
taculocysts) 

FEHOMEDUS^ 

(Umbrella  conical  and 
divided  by  transverse 
constrictions ,-  four 
interradial  tentacu- 
locysts) 

CUBOMEDTJS^ 

(  Umbrella  four-sided, 
cup-shaped;  fourper- 
radiai  tentaculocysts) 


Suborders 


Genera 


Species 


DISCOMEDUS^ 

(Flattened,  saucer-like 
or  disk-shaped  um- 
brella ;  radial  tubes 
branched;  eight  ten- 
taculocysts) 


CONNOSTOM^ 

(  Very  small;  marginal 
tentacles;  short  and 
solid;  7nouth  square 
without  arms) 


Lucernaria    L,  auricula 


Pericolpa       P.  quadrigata 


Charybdwa    C  marsupialis 


Aurelia 

Cyanea 

Linerges 
Pelagia 


SEMOSTOMiE 

(Square  mouth  with 
four  long  arms;  tenta- 
cles long  and  hollow) 

RHIZOSTOM^ 

("'  Root-mouth  "^ 
(Mouth    obliterated    ^y    •  ^-^ 
growth    of  oral  arms  ^  CaSSlOpeia 

across  it;  tentacles  ab- 
sent) 

133 


i 


'■I 


A,  flavidula 
C.  arctica 
C,  f'ulva 
C,  versicolor 
L,  tnercurius 
P.  cyanella 

C,  frondosa 


CLASS  SCYPHOZOA 

THE  LARGE  JELLYFISHES 

THERE  is  perhaps  no  marine  animal  which  excites  more  wonder 
than  the  jellyfish.  Its  transparency,  its  graceful  rhythmical 
movements,  its  long  streaming  tentacles,  the  variety  and  eccen- 
tricity of  its  form,  and  often  of  its  color,  attract  attention,  and 
one  naturally  desires  to  know  something  of  its  life-history.  Jelly- 
fishes  are  also  called  medusce,  because  their  long  appendages  sug- 
gest the  locks  of  the  Gorgon ;  acaleplis,  on  account  of  their  stinging 
or  nettle-like  properties  5  and  sun-jellies,  sea-blubbers,  etc.,  be- 
cause they  fioat  upon  the  surface  during  the  warmest  part  of  the 
day,  when  the  sun  is  high.  The  name  jellyfish  is  inappropriate, 
since  the  animal  in  no  way  resembles  a  fish  except  in  the  fact 
that  it  swims ;  but  it  is,  nevertheless,  the  commonest  name. 

Jellyfishes  vary  in  size  from  that  of  a  pinhead  to  six  or  seven 
feet  in  diameter.  They  differ  in  the  number,  size,  and  position 
of  the  tentacles,  the  number  of  the  radial  canals,  the  form  of  the 
manubrium,  the  position  of  the  egg-sacs,  etc. ;  but  the  general 
plan  of  the  internal  structure  is  the  same  in  all  species.  In  shape 
they  are  compared  to  a  mushroom.  From  the  center  of  an  um- 
brella-like top  falls  a  central  organ  like  the  stalk  of  a  mushroom. 
It  is  called  the  manubrium  and  is  the  mouth  and  stomach  of  the 
animal. 

From  the  top  of  the  manubrium  radiate  straight  or  branched 
tubes,  which  are  connected  with  a  canal  which  runs  around  the 
whole  margin  of  the  umbrella.  Extending  around  the  inner 
circumference  of  the  disk  in  certain  species  (usually  the  hydroid 
medusae),  there  is  a  horizontal  shelf,  called  the  velum,  or  veil,  be- 
cause it  sometimes  falls  like  a  veil, 

134 


JELLYFISHES  135 

From  the  margin  of  the  umbrella  depend  the  tentacles.  There 
are  little  mineral  deposits,  like  crystals,  called  litJiocysts,  disposed 
at  intervals  on  the  margin,  and  known  also  as  marginal  hodies, 
which  are  supposed  to  be  eyes.  In  some  species  these  lithocysts 
are  inclosed  in  club-shaped  bodies,  and  they  are  then  called  ten- 
taciilocysts,  because  they  are  like  small  tentacles.  These,  together 
with  the  nerve-fibers,  are  called  the  sense-organs;  but  to  what 
extent  jellyflshes  can  see  and  feel  is  undetermined.  This  is  the 
first  appearance  of  sense-organs  in  animals.  Ai'ound  the  con- 
cave surface  of  the  umbrella  is  a  muscular  zone,  or  zone  of  con- 
tractile tissue,  by  which  the  animal  opens  and  shuts  the  umbrella 
and  gets  its  locomotive  power.  The  gonads,  which  are  con- 
spicuous from  being  more  opaque  than  the  rest  of  the  body,  are 
the  egg-  or  sperm-sacs.     They  vary  in  form  and  in  position. 

The  jellyfish  is  carnivorous,  feeding  on  small  organisms  such 
as  crustaceans  and  even  fishes.  The  tentacles  are  invested  with 
stinging-cells,  as  are  also  the  frills  about  the  mouth,  when  such 
occur.  With  these  stinging-cells,  which  are  in  some  species  so 
powerful  as  to  have  been  compared  with  an  electric  battery,  the 
jellyfish  benumbs  its  prey.  The  stinging  properties  are  due  to 
nettle-like  threads  contained  in  poison-cells.  When  these  pene- 
trate the  flesh  they  produce  a  pain  similar  to  that  of  an  electric 
shock. 

The  food  is  taken  into  the  manubrium  by  the  square  mouth  at 
its  free  end,  and  is  there  digested.  It  is  then  sent  as  nutritive 
fluid  through  the  canal  system  of  the  body,  and  ejected  through 
small  pores  in  the  canal  which  surrounds  the  margin  of  the 
umbrella. 

There  are  two  sexes.  The  gonads  of  the  female  contain  eggs ; 
those  of  the  male,  sperms.  The  contents  of  the  gonads  drop 
into  the  central  cavity  and  pass  out  through  the  mouth.  The 
fertilized  ovum  is  called  a  planula,  and  is  a  transparent  sphere 
covered  with  cilia,  by  means  of  which  it  swims  about  for  a  time. 
At  length  it  attaches  itself  to  some  object,  and  becomes  in  some 
species  a  branching  colony  (hydroid),  in  other  species  a  strohila. 
The  latter,  as  it  grows,  is  constricted  at  intervals,  and  at  maturity 
resembles  a  pile  of  inverted  saucers  with  lobed  edges.    Each  of 


136  MARINE  INVERTEBRATES 

these  saucers  is  finally  detached,  and  when  liberated  is  called  an 
ephyrula,  and  becomes  a  jellyfish.  Thns  its  cycle  of  life  is  com- 
plete. There  are  some  species  which,  having  no  hydroid  or  strobila 
state,  mature  without  alternation  of  generation  (metagenesis). 

The  term  of  life  of  the  jellyfish  does  not  exceed  one  year. 
Even  the  giant  Cyanea  attains  its  immense  growth  in  six  months. 
It  starts  in  the  spring  as  an  ephyrula,  not  more  than  one  half  of 
an  inch  in  diameter,  and  when  it  dies  in  the  autumn  is  often  six 
to  eight  feet  in  diameter.  The  bodies  of  jellyfishes  are  ninety- 
nine  per  cent,  water,  and  the  dead  ones  thrown  upon  the  beaches 
by  the  autumn  storms  rapidly  disappear,  leaving  no  traces  behind. 

The  powerful  stinging-cells  with  which  the  large  medusae  are 
armed  make  them  formidable  enemies,  and  it  is  probable  that 
some  deaths  by  drowning  are  caused  by  swimmers  encountering 
them  and  becoming  paralyzed  by  them. 

ORDER  STAUROMEDUS^ 

('"  Cross-medusce  ") 

Genus  Lucemaria 

L,  auricula.  This  little  iridescent  jellyfish,  which  measures  about 
one  and  a  half  inches  in  diameter,  is  commonly  found  attached  to  eel- 
grass  by  a  stalk-like  projection  of  the  top  of  the  umbrella.  Short,  globe- 
tipped  tentacles  are  arranged  in  eight  clusters,  each  cluster  on  a  raised 
prolongation  of  the  margin  of  the  umbrella,  and  in  the  center  of  each 
space  between  them  is  a  dark  kidney-shaped  organ  called  the  anchor. 
These  anchors  are  used  for  holding,  either  for  suspension  or  when  moving 
from  place  to  place.  The  mouth  forms  ashght  quadrangular  projection 
in  the  center  of  the  bell-like  expansion .  The  arm-hke  projections  are  mot- 
tled with  two  rows  of  spots,  which  are  the  ova.  Although  a  free  form 
and  capable  of  moving  about,  Lucemaria  is  sedentary  in  habit.  It  is 
sometimes  found  free,  but  generally  attached  by  its  extremity  to  eel- 
grass  or  Fucus,  seldom  to  rocks.  It  is  constantly  changing  its  shape. 
The  one  it  most  frequently  assumes  is  that  of  a  cup  or  inverted  beU.  It 
is  found  on  the  New  England  coast.    (Plate  XLIV.) 

ORDER  PEROMEDUS^ 

(^'Maimed  medusce^^) 

GrENUs  I^ericolpa 

P.  quadrigata.  Umbrella  conical  and  divided  by  a  horizontal  con- 
striction into  two  parts,  the  lower  one  being  again  divided  into  lobes. 
There  are  four  long  tentacles  and  four  tentaculocysts.  It  is  not  found 
on  the  coasts  of  the  United  States. 


JELLYFISHES 


137 


ORDER  CUBOMEDUS^ 

(^'  Cube-medusce^'') 

Genus   Chary bdcea 

C,  marstipialis.  Umbrella  square,  flattened  on  top,  and  of  firm 
consistency.  Four  tentacles  fall  from  lobes  on  the  umbrella,  and  four 
club-shaped  eyes  are  in  marginal  notches.  Plate-like  egg-sacs  follow 
each  side  of  the  four  radial  canals.  The  bell  is  one  inch  in  diameter  and 
about  two  inches  in  height.  It  is  not  found  on  the  coasts  of  the  United 
States. 

ORDER   DISCOMEDUSiE 

( ' '  Disk-mediisce ' ') 

Suborder  SEMOSTOMiE 

Genus  Aurelia 

A,  flavidiila.  Size  eight  to  ten  inches  in  diameter ;  disk  gelatinous, 
transparent  bluish-white,  broad  and  comparatively  flat,  with  a  fringe  of 
short  tentacles  of  even  length  around  the  margin ;  margin  broken  by 
eight  notches,  in  each  one  of  which  is  a  club-like  organ  {tentaculocyst)  con- 
taining calcareous  spots  or  eyes,  which  are  hidden  by  lappets  or  hood- 
like coverings  -,  groups  of  nerve- 
cells  also  lie  in  the  marginal 
notches;  radial  canals  branched; 
manubrium  very  short,  with 
square  mouth,  which  is  sur- 
rounded by  delicate  membranes, 
or  oral  arms,  each  arm  being 
a  folded  membrane  tapering  to 
a  point.  The  edges  of  tho  mem- 
branes are  covered  with  lasso-  or 
stinging-cells.  Four  egg-sacs, 
or  gonads,  are  conspicuous  in 
horseshoe  shape  around  the 
center  of  the  disk.  The  gonads 
are  pink  in  the  males,  and  yellow 
in  the  females.  These  medusae 
swim  in  shoals,  and  are  common 
everywhere  in  summer.  They 
may  be  said  to  be  annual  ani- 
mals, for  they  make  their  ap- 
pearance regularly  as  free- 
swimming  medusae  in  the  latter 
part  of  April,  when  they  may  be 

seen  in  immense  numbers  near  the  surface  when  the  water  is  smooth  and 
the  sky  clear.  At  this  time  they  are  about  an  inch  in  diameter.  They 
grow  rapidly,  and  by  the  end  of  June  have  attained  their  full  size.     At 


Aurelia  flavidula,  about  one  f  ourtli  natural  size. 


138 


MARINE   INVERTEBRATES 


Strobila  of  Aurelia  flavidula. 


the  end  of  July  they  are  fully' developed,  and  begin  to  discharge  their  eggs, 
which  go  into  the  folds  around  the  mouth  and  remain  there  until  they  at- 
tain the  planula  stage.  After  the  spawning 
period  the  medusse,  reduced  in  strength,  are 
unable  to  resist  the  storms  of  the  autumn, 
and  many  of  them  are  cast  ashore  ',  many 
others,  in  a  more  or  less  wasted  condition, 
float  near  the  surface,  but  the  body  is  less 
transparent,  its  tissues  are  thickened,  its 
tentacles  gone,  and  general  dissolution  has 
commenced.  In  this  condition  the  medusae 
are  frequently  capsized  by  the  air  which  ac- 
cumulates in  the  empty  egg-cavities,  and, 
floating  helplessly  on  the  surface,  are  at- 
tacked and  destroyed  by  swarms  of  small 
crustaceans ;  thus  their  cycle  of  life  is  ter- 
minated. It  has  been  suggested  that  the 
destruction   of  the  mothers,  by  being  cast 

upon  the  beaches  in  the  autumnal  gales,  is  a  provision  to  set  free  the 
planulse  in  a  position  favorable  to  their  existence ;  for  when  liberated 

they  fasten  upon  the  rocks  and  sea- 
weeds of  the  shore,  where,  during  the 
winter  months,  they  develop  into  stro- 
bilse,  which  in  turn  free  their  saucer- 
like disks  early  in  April. 

Genus  Cyanea 

C,  arctica,  the  sun- jelly  or  sea- 
blubber.  This  is  the  largest  jellyfish 
known.  Some  individuals  measure 
seven  and  a  half  feet  across  the  disk 
and  have  tentacles  more  than  one 
hundred  feet  long.  Usually  they  are 
three  to  five  feet  in  diameter,  with 
tentacles  thirty  to  forty  feet  long.  The 
disk  is  red,  the  margin  white  and  scal- 
loped. The  tentacles,  of  different 
colors,  are  covered  with  lasso-  or  sting- 
ing-cells, and  are  arranged  in  eight 
distinct,  thick  clusters  on  the  margin. 
From  the  mouth  hang  four  long  and 
very  broad,  thin  curtains,  much  folded 
and  ruffled,  whose  edges  at  times  look 
as  if  they  were  embroidered,  because 
great  numbers  of  discharged  eggs  are 
attached  to  them .  Four  egg-sacs  hang 
from  the  disk  near  the  manubrium,  and 
eight  sense-organs  (tentaculocysts),  in 
hardened  coverings,  lie  in  some  of  the 

Cyanea  arctica,  greatly  reduced  in  size.  deep  iucisioUS  of  the  margin.       CyaneO, 


JELLYFISHES 


139 


is  usually  solitary,  seldom  being  seen  in  company  with  others.  It  is  com- 
mon on  the  New  England  coast,  and  is  frequently  found  stranded  on  the 
beach,  where  it  in  no  way  suggests  the  beautiful  appearance  it  pre- 
sents when  floating  in  the  water.  Like  Aurelia,  Cyanea  has  a  strobila 
stage.  It  is  supposed  that  the 
young  remain  near  the  bottom, 
for  they  are  seldom  seen,  while 
adults  are  plentiful.  They  begin 
to  appear  in  numbers  at  the  end 
of  summer  from  Cape  Cod  north- 
ward. 

C,  fulva.  This  species  is  found 
in  midsummer  south  of  Cape  Cod 
and  is  common  in  Long  Island 
Sound.  Its  general  color  is  light 
yellowish-brown,  the  flowing  cur- 
tains being  the  darkest  part  of 
the  animal.  It  is  not  as  large  as 
C.  arctica,  and  the  lobes  of  the  mar- 
gin are  deeper  and  more  rounded. 

C.  versicolor.    The  whole  disk 
is  bluish  milky-white,  the  flowing  curtains  are  light  brown,  and  the 
tentacles  are  pink.     It  is  not  so  large  as  C.  arctica.    Found  in  the  spring 
on  the  southern  coast. 

Genus  Lifierges 

L,  mercuriiis,  the  thimble-flsh.  The  English  name  indicates  the 
form  as  well  as  the  size  of  this  httle  brownish  jellyfish,  which  is  found 
near  the  Florida  Keys,  extending  in  lines  for  considerable  distances. 


Linerges  mercurius,  thimble-fish. 


Genus  I^elagia 

J*,  cyanella.  Umbrella  spherical,  margin  scalloped,  tentacles  eight 
in  number ;  four  long  appendages  ruffled  on  the  edges  hang  from  the 
mouth ;  size  about  two  inches  in  diameter  -,  appendages  four  inches 
long;  color  pink.     (See  next  page.) 

Suborder  RHizosTOM^ffi 

The  Rhizostomae^  or  root-mouth  jellyfishes,  are  very  remark- 
able. They  have  no  tentacles,  but  covering  the  end  of  the  manu- 
brium and  hanging  from  it  like  tentacles  are  oval  appendages 
with  numerous  minute  funnel-like  apertures,  called  suctorial 
mouths.  As  the  manner  of  locomotion  of  jellyfishes  is  peculiar 
to  themselves,  so  also  is  this  many-mouthed  development  unique 
in  the  animal  kingdom.  The  type  of  this  group,  described  below, 
is  found  on  the  Florida  Keys.  The  different  species  vary  in 
diameter  from  three  to  eight  inches. 


140 


MARINE  INVERTEBRATES 


Genus  Cassiopeia 


Pelagia  cyanella. 


Cfrondosa,  This  species 
has  a  circular  disk,  on  the 
margin  of  which  are  sixteen 
sense-organs  (tentaculocysts), 
but  no  tentacles.  The  lower 
end  of  the  manubrium,  which 
in  other  jellyfishes  is  an  open 
mouth,  is  closed  by  eight  arms 
which  emanate  from  it  and  are 
usually  extended  laterally,  ly- 
ing parallel  to  the  disk.  These 
arms  are  much  branched,  and 
the  branches,  in  turn,  have 
numerous  appendages.  Some 
of  these  appendages  look  like 
little  polyps  and  have  mouths 
surrounded  by  crowns  of  ten- 
tacles ;  others  are  ovoid  bodies 
without  external  openings,  but 
with  a  central  cavity  connected 
with  vessels  leading  to  the 
arms.  The  former  are  mouths, 
but  the  function  of  the  ovoid 
bodies  is  not  known.  Although 
able  to  swim  freely,  Cassiopeia 
lies  usually  on  its  back,  as  if 
attached,  and  languidly  opens 
and  closes  its  disk,  rarely 
changing  its  position.  Its  arms, 
extending  upward,  appear  like 
the  fronds  of  algse.  These 
jellyfishes  are  common  on  the 
Florida  coast,  huddled  together 
on  the  sands  of  the  coral  reefs. 
(Plate  XLIV.) 


TABLE   SHOWING  THE  CLASSIFICATION  OF   THE  ACTINOZOA 
DESCRIBED  IN   THIS  CHAPTER 

Class 
ACTINOZOA 


Subclass 

Zoantharia 

(Mesenteries  numerous,  usually  in  multiples  of  six ;  tentacles  unbranched  hollow  cones) 


Orders 

ACTINIARIA 

(The      -sea-anemones. 
Single ;  no  skeleton) 


MADREFORARIA 

(The  stone-  or  reef -cor- 
als. Colonies;  skele- 
ton calcareous) 


Genera 
'Metridiiim 
Mhodactinia 
Holocampa 
^Sagartia 
Oculina 
Astrcea 
Meandrina 
I>iploria 

Madrepora 
Astrangia 


Species 
M,  tnarginatum 
JR,  davidsii 
H,  producta 
S.  leucolena 


D,  cerebriformis 
( M.  cervicomis 
\  M,  palmata 

Am  danae 


ANTIPATHARIA 

(The  black  corals) 

Subclass 
Alcyonaria  or  Halcyonoida 

(Tentacles  and  mesenteries  eight  in  number ;  tentacles  feathered,  that  is,  with  uniform 

branches) 


ALCYONACEA 

GORGONACEA 

(The  sea-fans  and  sea- 
%vhips.  Compound, 
tree-like  colonies,  tvith 
horny  axis,  branching 
throughout) 

PENNATULACEA 

(Free,  phosphorescent; 
colonies,  with  horny 
axis  ;  polyps  in  lat- 
eral branches) 


(  Alcyonium 
\  TuMpora 


A,  palmatum 


Pennatula 


141 


CLASS  ACTINOZOA 

SEA-ANEMONES,  REEF-CORALS^  SEA-FANS,  SEA- WHIPS,  AND  SEA-PENS 

THE  animals  of  this  class  are  divided  into  two  subclasses, 
based  on  the  following  anatomical  differences :  In  the  first 
subdivision,  which  includes  the  sea-anemones  and  the  reef -build- 
ing corals,  the  polyps  have  numerous  simple,  hollow  tentacles  and 
radial  partitions  of  the  same  number,  both  being  some  multiple 
of  six.  The  polyps  of  a  colony  are  all  alike,  and  the  hard  matter 
they  secrete  is  carbonate  of  lime.  In  the  second  subdivision, 
the  Alcyonaria, — or  halcyonoids,  as  they  are  commonly  called, — 
the  tentacles  and  radial  partitions  are  always  eight  in  number, 
and  the  tentacles  have  small  symmetrical  appendages  or  branches. 
The  polyps  of  this  group  are  often  accompanied  by  small  zooids 
having  no  tentacles.  The  hard  secretions  are  horny  and  elastic, 
as  in  sea-fans,  sea- whips,  and  sea-pens,  or  they  are  extremely  hard, 
as  in  Corallina  rubrum. 

SUBCLASS  ZOANTHARIA 

C ' '  Animal-floivers ' '') 

ORDER  ACTINIARIA 

SEA-ANEMONES 

These  curious  and,  at  times,  beautiful  creatures  are  polyps,  and 
are  constructed  on  the  radial  system.  They  have  a  cylindrical  body 
with  a  broad  base  and  rows  of  hollow  tentacles  around  the  upper 
disk.  They  have  a  central  sac,  and  a  space  between  the  outer  and 
inner  sacs  which  is  divided  vertically  by  walls  called  mesenteries , 
as  explained  on  page  114.     Each  tentacle,  however  many  there 

142 


SEA-ANEMONES  143 

may  be,  has  a  corresponding  chamber.  The  inner  sac  has  a  mouth, 
like  a  slit,  at  the  top  of  the  disk,  opening  to  the  outside,  and  it 
also  has  openings  into  the  chambered  spaces  which  surround  it. 
These  chambers  also  open  into  the  hollow  tentacles  5  thus  a  con- 
tinuous circulation  throughout  the  whole  animal  is  established. 

The  food  taken  in  at  the  mouth  is  digested  in  the  inner  sac, 
passes  through  all  the  chambers  of  the  cavity  as  nutritive  fluid,  and 
is  then  expelled  at  the  mouth  again.  The  inner  sac,  or  gullet,  has 
longitudinal  grooves  ;  two  of  these  are  broad  and  deep,  and  corre- 
spond to  the  corners  of  the  mouth.  These  are  called  siplionoghjplis. 
The  sea-anemone  is  soft  and  contractile,  and  belongs  to  the  only 
order  of  this  class  which  does  not  secrete  a  skeleton.  It  has  two 
sets  of  muscles,  one  of  which  extends  from  the  base  to  the  sum- 
mit of  the  body  and  is  placed  on  the  dividing  partitions.  Sea- 
anemones  are  classified  by  the  arrangement  of  the  septa  and  the 
manner  in  which  the  muscles  are  placed  upon  them.  The  other 
set  of  muscles  is  arranged  around  the  circumference  of  the  col- 
umn or  body.  Each  tentacle  is  furnished  with  similar  sets  of 
muscles.  The  animal  is  sensitive,  and  at  the  least  alarm  con- 
tracts its  body  by  means  of  these  muscles,  and  quickly  trans- 
forms itself  from  a  beautiful,  flower-like  form  into  a  shapeless, 
unattractive,  inconspicuous  mass. 

The  Actiniaria  are  developed  from  the  egg.  The  eggs  form 
on  the  edges  of  the  inner  walls  (mesenteries),  and  when  mature 
drop  into  the  outer  sac  (gullet),  and  out  of  the  mouth  as  ciliated 
spheres  (planulae).  After  swimming  about  for  a  time  these  at- 
tach themselves  to  rocks,  and,  conforming  to  the  irregularities  of 
the  surface,  secure  a  tight  hold.  The  upper  surface  of  the 
planula  then  becomes  depressed  and  forms  a  gullet,  and  in  time  a 
complete  animal  is  formed.  The  Actiniaria  reproduce  also  by 
budding.  A  small  protuberance  or  simple  elevation  of  the  body- 
wall  appears  on  the  side  at  the  base,  or  in  some  species  on  the 
disk  of  the  animal,  which  generally  develops  into  a  complete 
animal  and  at  maturity  falls  away  from  the  parent.  Sometimes 
several  anemones  bud  simultaneously  from  the  same  individual, 
and  a  third  generation  commences  to  bud  at  the  same  time  from 
the  immature  young  of  the  parent  stock.     The  sea-anemones  in- 


144  MARINE  INVERTEBRATES 

crease  also  by  self-division.  In  this  case  a  constriction  is  formed, 
which  gradually  deepens  and  forms  a  complete  partition  of  the 
body,  and  two  individuals  exist  where  originally  there  was  but  one. 

The  Actiniaria  are  carnivorous  and  very  voracious.  They  feed 
on  small  organisms  and  on  shell-fish  and  crustaceans,  which  they 
suck  out  of  their  shells.  To  secure  their  prey  they  are  armed 
with  an  abundant  supply  of  stinging-cells  on  the  tentacles,  and 
also  with  fine  stinging-threads  which  are  ejected  from  pores 
which  are  distributed  over  the  whole  body. 

Sea-anemones  vary  greatly  in  color  and  form,  and  when  ex- 
panded suggest  flowers,  but  do  not  resemble  the  one  for  which 
they  are  named.  They  abound  on  every  shore,  the  same  genus 
often  being  found  in  widely  separated  regions.  They  are  larger 
and  more  highly  colored  in  tropical  waters.  Many  of  the  species 
are  littoral,  and  are  found  in  the  tide-pools  of  rocky  caverns, 
on  the  under  side  of  rocks,  and  on  the  piles  of  wharves  and 
bridges  at  low- water  mark.  The  majority  of  them  are  attached, 
but  are  able  to  change  their  location  j  others,  Edwardsia  and 
Cerianthus,  swim  about  when  young,  and  in  the  adult  state  burrow 
in  the  sand  or  mud,  leaving  only  their  tentacles  exposed.  Bucid- 
ium  parasiticiim  is  parasitic  on  the  folds  of  the  membrane  which 
hangs  from  the  mouth  of  the  large  jellyfish  Cyanea  arctica.  Fenja 
and  Feachia  lie  on  the  sea-bottom,  with  their  bodies  horizontal 
like  a  worm,  the  mouth-end  and  tentacles  erect. 

Adamsia  palUata  furnishes  another  example  of  commensalism ; 
it  lives  on  the  back  of  shells,  commonly  the  whelk,  inhabited  by 
hermit-crabs.  Minyas  is  pelagic ;  it  has  a  float  at  one  end,  and  by 
means  of  its  tentacles  swims  about  freely. 

A  very  few  species  only  are  described  below,  since  these  polyps 
are  unmistakable,  being"  always  columnar  bodies,  with  the  upper 
disk  more  or  less  crowded  with  tentacles,  and  so  brilliant  in  col- 
oring and  beautiful  in  form  as  to  attract  attention  if  found  in 
the  expanded  state  5  otherwise  they  are  easily  overlooked. 

Genus  Metridium 

M,  marginatum.  This  is  the  most  conspicuous  and  abundant  sea- 
anemone  of  the  northeastern  coast.      It  is  common  from  New  York 


SEA-ANEMONES  .  145 

northward,  and  is  found  near  low- water  mark  in  tide-pools,  on  the  under 
side  of  large  stones,  in  sheltered  crevices  of  rocks,  and  on  the  piles  of 
wharves  and  bridges.  In  contraction  it  is  a  broad,  low  cone,  but  when 
expanded  is  sometimes  ten  inches  across  the  disk.  Allied  species  found 
in  Florida  are  eighteen  inches  in  diameter.  The  column  is  smooth, 
cylindrical,  and  broader  than  long.  At  the  top  is  a  slightly  elevated, 
thickened  fold,  and  above  this  a  deeply  folded  and  frilled  margin,  with 
numerous  fine,  short  tentacles,  appeai-ing  like  a  fringe,  which  cover  the 
upper  side  of  the  disk  half-way  to  the  oval  mouth.  The  color  is  exceed- 
ingly variable ;  commonly  the  column  is  yellowish-brown,  but  it  may  be 
pink,  white,  salmon,  orange,  or  dark  brown,  or  striped  or  mottled  with 
different  colors.  The  disk  and  folds  are  lighter  or  flesh- colored,  and  the 
tentacles  are  of  varying  colors,  usually  grayish  with  tips  of  brighter 
colors.  When  irritated  this  species  throws  out  from  the  column  num- 
bers of  long,  slender  white  threads  (aeontia),  which  are  covered  with 
minute  stinging-cells.  These  organs  of  defense  protect  the  animal 
from  the  attacks  of  many  enemies. 


Genus  Hhodaetinia 

M.  davidsii  (Agassiz),  Tealia  crassifovfuis  (Gosse),  the  thick- 
petaled  rose-anemone.  The  color  varies,  being  often  bluish-green 
mottled  with  crimson,  often  bright  cherry-red,  with  the  thick  tentacles 
somewhat  lighter  in  shade,  or  flesh-colored.  The  animal  is  found  in 
shallow  water.  It  assumes  various  shapes,  changing  every  few  minutes. 
The  tentacles  are  short,  conical,  and  uniform  in  size ;  the  column,  the 
breadth  of  which  is  greater  than  its  height,  often  has  wart-like  processes 
in  longitudinal  lines.  The  diameter  of  the  disk  is  about  three  inches. 
Found  from  Cape  Cod  northward  in  tide-pools  and  on  ledges  covered 
with  Fucus. 

Genus  Holocampa 

H,  producta.  Its  column,  stretched  to  its  full  extent,  is  a  foot  in 
length  and  about  an  inch  in  diameter,  but  when  contracted  is  much 
shorter  and  thicker.  It  has  but  twenty  tentacles,  and  these  have  swollen 
tips.  Rows  of  suckers  extend  the  length  of  the  column.  It  ranges  from 
Cape  Cod  to  South  Carolina,  and  is  found  under  rocks  at  low-tide  mark, 
and  also  on  sandy  beaches,  buried  in  the  sand,  with  its  tentacles  only 
above  the  surface. 

Genus  Sagartia 

S.  leucolena,  the  white-armed  anemone.  It  ranges  from  Cape  Cod 
to  North  Carolina,  and  is  common  in  Long  Island  Sound,  being  found  at 
low-water  mark  on  the  under  side  of  stones.  The  column  is  elongated, 
cylindrical,  translucent,  flesh-colored,  with  simple  plain  disk  and  long, 
slender,  whitish  tentacles  crowded  together  near  the  margin. 

10 


146  MARINE  INVERTEBRATES 

ORDER  MADREPORARIA 

STONE-  OR    REEF-CORALS 

The  coral  resembles  the  sea-anemone  and  is  a  polyp  con- 
structed on  the  radial  plan  (page  113).  It  lives  in  colonies,  but, 
unlike  the  hydroid  colonies,  each  polyp  of  the  community  is  a 
complete  organism,  and  in  the  reef-building  corals  all  the  indi- 
vidual polyps  of  a  colony  are  alike.  The  home  of  each  animal  is 
called  a  coralUte,  and  the  aggregation  of  many  corallites  is  a 
corallum. 

The  corallite  is  composed  of  carbonate  of  lime  secreted  by  the 
polyp,  and,  broadly  speaking,  may  be  called  a  skeleton.  The 
secretion  forms  a  basal  plate  and  radiating  partitions  between 
the  mesenteries  in  the  cavity  of  the  animal,  and  also  surrounds 
the  polyp  like  a  cup.  In  some  species  this  is  a  solid  substance ; 
in  others  it  is  like  a  network  through  which  the  animal  sub- 
stance (coenosarc)  of  the  zooids  of  the  colony  is  connected,  as  in 
Madrepora. 

The  polyps  reproduce  by  budding  and  by  self-division  (fission), 
in  a  manner  similar  to  that  of  sea-anemones.  The  way  in  which 
the  budding  or  the  fission  .takes  place  determines  the  shape  of 
the  colony,  or  corallum,  which  has  a  great  variety  of  forms.  In 
some  species  the  budding  is  confined  to  certain  individuals  of  the 
colony.  In  this  case  the  branched  forms  result.  When  growth 
takes  place  by  fission,  hemispherical  masses  are  formed,  which 
are  often  perfectly  symmetrical,  as  in  the  so-called  brain-corals. 
In  Astrma  the  polyps  are  inclosed  separately,  but  in  Meandrina 
fission  is  confined  to  the  upper  half  of  the  polyps,  so  that  a  com- 
plex polyp  is  formed,  with  several  mouths  opening  into  a  common 
stomach,  making  long  serpentine  furrows  on  the  corallum. 

Some  of  the  genera  of  the  second  subdivision,  the  alcyonarians, 
differ  materially  from  the  ordinary  idea  of  corals,  as  their  frame- 
work is  of  a  horny  and  more  or  less  flexible  material  (chitin). 
Of  these  are  the  sea-fans,  sea-whips,  and  sea-pens.  The  organ- 
pipe  coral  of  the  same  subdivision  is  an  example  of  an  exceed- 
ingly fragile  lime  structure,  while  the  red  coral,  CoralUna  nibrum^ 


CORALS  -  147 

the  species  so  much  used  for  ornamental  purposes,  has  an  exceed- 
ingly hard  and  stony  character.  The  madrepore  corals  are  called 
reef -builders,  but  not  in  the  sense  of  constructors  of  reefs.  They 
do  not  erect  definite  structures  as  bees  do.  It  is  the  aggregation 
of  the  skeletons  of  the  dead  polyps,  together  with  other  agencies, 
which  forms  a  reef.  The  coral  polyps,  though  so  minute  individ- 
ually, are  almost  infinite  in  numbers.  It  is  estimated  that  the 
colonies  rise  one  half  of  an  inch  in  ten  years. 

Corals  live  at  different  depths  in  the  sea.  Those  which  form 
the  base  of  the  reef  are  the  astrseans,  which  do  not  live  above  a 
depth  of  six  fathoms.  They  are  characterized  by  little  star-shaped 
spots  on  the  corallum,  the  radial  partitions  meeting  in  the  center 
of  the  spots,  or  corallites.  Next  above  the  astraeans  come  the 
maeandrinas  and  the  porites.  The  former  have  elongated  openings 
which  extend  in  waving  furrows  over  the  surface.  The  porites 
resemble  astrasans,  but  the  pits  are  smaller,  with  fewer  partitions, 
and  the  substance  is  more  porous.  Above  these  and  capping 
the  reefs  are  the  beautiful  branching  and  palmate  madreporians, 
together  with  millepores,  numerous  varieties  of  sea-fans  {Oor- 
gonacea),  and  the  calcareous  seaweeds  (nullipores),  making  a 
garden  of  beautiful  branching  forms  of  every  shape  and  color. 

The  coral  reef  is  as  thickly  inhabited  by  other  living  organisms 
as  is  the  forest  by  birds  and  insects.  Mollusks,  worms,  crabs, 
starfishes,  and  sea-urchins  find  resting-places  there  and  work 
destruction  to  the  coral  masses,  as  they  bore  and  penetrate  the 
reef  in  various  ways  until  large  fragments  of  it  are  detached  and 
either  washed  by  the  waves  to  places  far  from  their  foundation, 
or  ground  to  sand,  which,  filling  the  interstices  of  the  reef,  adds 
to  its  solidity. 

The  living  coral  is  quite  different  in  appearance  from  the 
bleached  skeletons  commonly  seen.  The  surface  of  the  corallum 
is  often  soft  and  downy,  from  the  numerous  waving  tentacles, 
and  its  coloring  is  vivid  and  varied.  The  madrepores  are  pink, 
yellow,  green,  brown,  and  purple.  Tubipora,  the  organ-pipe  coral, 
has  green  polyps  emanating  from  its  red  tubes.  White  polyps  in 
star-like  form  dot  the  branches  of  the  red  coral  of  commerce, 
CoralUna  nihrmn.     The  whole  mass  of  Helipora  is  bright  blue, 


148  -  MARINE  INVERTEBRATES 

and  the  beautiful  sea-pens  are  both  highly  colored  and  phos- 
phorescent. Owing  to  the  fact  that  these  brilliantly  colored 
polyps  were  mistaken  for  blossoms,  the  recognition  of  their  true 
character  was  long  delayed,  they  having  been  ranked  as  vege- 
tables until  comparative!}^  recent  times. 

With  few  exceptions,  corals  do  not  grow  in  water  below  the 
temperature  of  68°,  hence  they  are  inhabitants  of  tropical  and 
subtropical  waters.  The  Florida  Keys  are  coral  reefs,  and  the 
species  described  below  are  to  be  found  there^ 

Genus  Oculina 

Arborescent ;  corallites  arranged  somewhat  spirally  on  branches 
and  widely  separated;  branches  compact  between  corallites. 
Each  bud  is  for  a  time  at  the  apex  of  the  branch,  but  finally  be- 
comes lateral,  and  then  gives  off  another  bud  from  its  upper  sur- 
face, and  so  the  stem  lengthens.     (Plate  XLIY.) 

Genus  Astrcea 

The  star-corals.  The  corals  of  this  genus  are  hemispherical 
masses  covered  with  small  star-shaped  pits,  or  corallites.  Although 
the  diameter  of  an  astraBa-dome  may  be  twelve  feet  or  more, 
it  has  only  one  half  or  three  quarters  of  an  inch  of  living  coral 
on  its  surface,  the  rest  being  solid  matter  left  behind  as  the 
polyps  rose  in  growth.  The  colony  increases  by  self-division. 
The  septa  meet  in  the  center  of  the  corallite,  making  star-like 
pits ;  the  surface  is  comparatively  smootho     (Plate  XLIV.) 

Genera  Meandrina^  JDiploria 

Corallum  massive,  hemispherical  in  shape,  with  furrows  running 
in  irregular  lines  over  the  whole  surface.  The  peculiar  serpentine 
form  of  the  corallite  is  produced  by  the  animal  growing  in  one 
direction,  fission  being  incomplete,  and  new  mouths  being  succes- 
sively opened  until  a  line  of  them  extends  along  a  common  stomach. 

D.  cerebriformis.  This  species  is  commonly  known  as  brain-coral 
or  brain-stone.  The  hemispherical  shape,  together  with  the  peculiar 
serpentine  corallites,  makes  its  resemblance  to  the  human  brain  very 
noticeable  and  the  name  unusually  appropriate.  This  species,  when 
living,  is  bright  yellow.     (Plate  XLV.) 


Millepora  alcicornis. 
Cassiopeia  frondosa. 
Oculina. 


PLATE   XLIV. 


Lucernaria  auricula. 
Astrsea  argus. 


PLATE   XLV. 


Porites  furcata  and  P.  astrseaoides.  Diplora  cerebriformis. 

Madrepora  cervicornis.  Madrepora  palmata. 

Mycedium  fragile. 


CORALS  149 

Genus  Madrepora 

Some  species  of  these  corals  appear  like  branches,  while  others 
have  flat,  low  surfaces  or  fronds;  all  of  them  are  covered  with 
innumerable  small  cylindrical  cupSo  Each  cup  is  the  home  of  a 
polyp,  which  secretes  calcareous  matter  around  its  column,  and 
septa  between  its  radial  partitions.  The  corallum,  when  ex- 
amined with  a  glass,  looks  like  meshwork.  Through  the  fine 
openings  of  the  porous  sui'face,  the  polyps  of  the  colony  are 
connected  by  interlacing  tubes  of  animal  substance  (coenosarc). 
The  polyps  of  the  madrepore  colonies  are  small  in  comparison 
with  the  connecting  structure,  which  becomes  very  massive ;  but, 
although  large,  the  corallum  is  fragile,  on  account  of  its  perfo- 
rated character  and  the  exceeding  delicacy  of  its  parts. 

In  species  which  form  incrustations,  new  polyps  arise  from 
tissue  which  spreads  beyond  the  corallites.  In  some  species  cer- 
tain polyps  and  corallites  increase  in  length,  growing  longitudi- 
nally, and  continually  form  buds  around  the  base.  This  manner 
of  growth  leads  to  the  formation  of  branches,  while  the  former 
manner  gives  lateral  extension.  Both  of  these  forms  of  budding 
may  take  place  at  the  same  time  in  the  same  colony.  The  mad- 
repores are  among  the  most  common  of  the  reef -builders.  They 
form  reefs  which  extend  for  miles  around  the  Florida  Keys. 

M,  cervicornis,  the  stag-horn  coral.  This  is  a  branching  species 
which  attains  large  size.  Its  manner  of  growth  is  as  follows  :  At  the  tip 
of  each  branch  is  an  individual  polyp,  which  is  larger  than  those  which 
surround  the  branch.  This  is  the  original  animal  which  started  the 
branch,  and  is  the  parent  from  which  all  the  others  on  the  branch  have 
budded.  The  large  terminal  polyp  buds  around  the  base  ;  a  surplus  of 
lime  also  collects  at  the  base  and  clogs  its  tissues,  so  that  it  no  longer 
can  perform  the  functions  of  life,  and  after  a  certain  period  the  base 
becorues  dead  matter.  The  polyp  on  the  upper  end  continues  to  live 
and  rises  above  the  excess  of  solid  matter.  At  the  same  time  it  con- 
tinues to  form  new  buds.  The  buds  become  independent  corallites  and 
secrete  an  excess  of  calcareous  matter  at  their  bases,  which  cements  them 
to  the  parent  stock  and  increases  the  thickness  of  the  branch.  Thus,  as 
the  original  polyp  constantly  rises  and  buds,  the  colony  assumes  a  stem- 
hke  form,  covered  with  numerous  individuals.  Certain  polyps  on  the 
main  stem  have  the  attributes  of  the  parent  animal.  These  start 
branches,  and  so  the  process  goes  on,  and  in  time  the  colony  becomes 
much  branched  and  arborescent  in  form.  In  the  living  coral  each  little 
polyp  is  like  a  minute  sea-anemone,  having  a  colored  cylindrical  body 
surrounded  on  its  upper  disk  with  numerous  tentacles.     (Plate  XLV.) 


150 


MARINE  INVERTEBRATES 


M»  palmata.  This  madrepore  grows  like  the  one  described  above, 
except  that  the  branches  do  not  remain  separated,  but  unite  or  grow 
together,  giving  broad,  flat  surfaces  which  resemble  fronds.  When 
carefully  examined  these  surfaces  show  striations  which  indicate  the 
course  of  the  branches.  The  strictures  forming  the  lobes  are  caused  by 
the  failure  of  the  branches  to  unite.  On  the  Carysfort  Reef  of  the 
Florida  Keys  this  species  covers  the  top  of  the  reef  for  several  miles, 
nearly  reaching  the  surface,  and  appears  like  a  vast  bed  of  low  yellow 
shrubbery.     (Plate  XLV. ) 

Genus  Astrangia 

A,  danae,  A  small  coral  found  on  the  New  England  coast.  It  lives 
in  the  clefts  of  rocks  in  small  patches,  sometimes  two  to  three  inches 
across  and  one  quarter  of  an  inch  or  more  high.  Frequently  it  is  like  a 
thin  crust  of  lime  covered  with  star-like  divisions.  Sometimes  it  forms 
branches.  The  living  animals  are  white,  and  when  expanded  rise  above 
the  cells  and  resemble  a  cluster  of  small  sea-anemones. 


SUBCLASS  ALCYONARIA  or  HALCYONOIDA 

In  this  subclass— the 
actinoid  corals— the  pol- 
yps are  of  two  kinds. 
The  smaller  are  without 
tentacles  and  are  called 
siphonozobids.  The 

larger  have  but  eight 
radial  partitions  and 
eight  tentacles.  This 
limitation  of  parts  places 
them  in  a  higher  rank 
than  the  corals  of  the 
first  subclass.  Another 
characteristic  of  these 
Jj  polyps  is  the  presence 
K^  of  symmetrical  branch- 
lets  on  the  tentacles, 
which  give  them  a 
feather-like  appearance. 
These  corals  are  called 

Alcyonium palmatum  :  A,  entire  colony;  B,  spicules.  naiCyOnOlClS. 


CORALS 


151 


Some  of  tliem  may  easily  be  fancied  to  have  been  selected  for 
halcyons'  nests,  as  the  name  suggests— the  sea-fans,  for  example. 

ORDER  ALCYONACEA 

Genus  Alcyonium 

A,  palmatiitn.  This  coral  community  is  found  sometimes  at  low- 
water  mark,  but  usually  in  deeper  water,  attached  to  shells  and  stones. 
It  is  commonly  known  as  dead-men's-flngers,  an  unpleasant  name 
given  it  by  fishermen  because  of  a  fancied  resemblance  to  a  human 
hand  with  only  the  stumps  of  the  fingers.  The  substance  of  the  coral 
is  semi-cartilaginous,  with  scattered  spicules  of  lime  which  give  it 
stability.  When  the  polyps  are  fully  extended  the  colony  is  rather  at- 
tractive in  appearance,  but  not  so  when  contracted.  It  is  found  in 
abundance  on  the  New  England  coast.  An  immense  Alcyonium^  Para- 
gorgia  arhorea,  grows  on  the  fishing-banks  off  Newfoundland,  and  is 
sometimes  brought  up  on  the  fishing-lines.  It  is  tree-like  in  form,  and 
measures  six  feet  or  more  in  length. 


Genus  Tiihipora 

The  organ-pipe  coral.     This  genus,  which  is  deep  red  in  color 
and  very  fragile,  consists  of  many  tubes  slightly  separated  from 


TuMpora,  organ-pipe  coral,  natural  size. 


152  MARINE  INVERTEBRATES 

one  anotlier,  but  connected  by  horizontal  platforms  at  short  in- 
tervals. The  form  of  reproduction,  by  budding,  in  this  colony  is 
peculiar  to  itself.  The  spicules  of  lime  secreted  in  the  polyp 
unite  or  fuse  into  a  tube  or  cylindrical  skeleton.  At  certain 
stages  of  development  the  polyp  sends  out  a  horizontal  expan- 
sion, which  unites  with  the  expansions  of  other  polyps  and  be- 
comes calcified,  forming  a  shelf  which  binds  the  tubes  together. 
From  the  top  of  the  platforms  other  corallites  are  formed,  and 
thus  a  colony  is  made,  which  broadens  as  it  rises  in  its  growth. 
The  body  of  the  polyp  is  green,  the  skeleton  red.  It  belongs  to 
the  East  Indian  seas  and  is  given  here  only  as  an  example  of  a 
peculiar  manner  of  growth. 

ORDER  GORGONACEA 

SEA-FANS,  SEA- WHIPS,  AND   SEA-FEATHERS 

These  are  compound,  tree-like  Alcyonaria,  with  a  calcareous  or 
horny  skeleton  which  forms  a  branched  axis  and  is  covered  with  a 
layer  of  united  polyps  having  spicules  of  lime  distributed  through 
the  mass,  which  give  some  firmness  to  the  bark-like  covering. 
Gorgonias,  in  great  variety,  grow  in  abundance  on  the  coral  reefs 
and  mud-flats  of  Florida,  forming  masses  of  low  shrubbery,  pink, 
yellow,  brown,  or  purple  in  color. 

The  sea-whips  and  sea-feathers  are  varieties  of  gorgonias, 
which  are  named  from  their  forms.  Some  have  shapes  which 
resemble  branching  shrubs;  others  are  long  unbranched  rods, 
either  straight  or  spiral.  They  attain  a  height  of  several  feet  and 
are  of  various  colors.  The  colony  has  a  horny  axis  surrounded 
by  a  living  mass  which  resembles  a  sheet  of  animal  matter.  This 
mass  consists  of  polyps  closely  united,  and  has  throughout  its  sub- 
stance spicules  of  carbonate  of  lime,  making  it  a  kind  of  calcare- 
ous crust  or  bark.  In  dried  specimens  this  becomes  very  brittle 
and  is  easily  broken  from  the  horny  axis.    (Plates  XL VI,  XL VII.) 

The  sea-fans  are  colonies  with  a  central,  horny,  flexible,  and 
much-branched  axis,  covered,  as  in  the  sea- whips,  with  a  layer  of 
united  polyps  containing  spicules  of  lime,  which  make  a  some- 


<tf 


Eugorgia  aurantica. 
Pterogorgia  acerosa. 


PLATE   XLVI. 
GORGONIAS. 


Muricea  specifera. 
Gorgonia  anceps. 


PLATE  XL VII. 


Leptogorgia  rigida  (a  gorgonia). 
Gorgonia  flabellum  (a  gorgonia). 


Eunicea  lugubris  (a  gorgonia). 
Leptogorgia  Agassizii  (a  gorgonia). 
Pennatula  borealis  and  P.  aculeata 
(sea-pens). 


SEA-FANS  AND   SEA-PENS  153 

what  firm  crust.  This,  in  dried  specimens,  breaks  off  readily. 
The  colony  branches  profusely,  or  rather  separates  by  fission,  in 
oue  plane,  the  large  and  small  branches  making  a  network  of 
fan-like  shape  and  often  of  great  fineness  and  intricacy.  These 
fans  attain  a  length  of  several  feet  and  a  corresponding  breadth, 
and  are  abundant  in  semi-tropical  as  well  as  in  more  southern 
waters.     In  color  they  are  red,  yellow,  brown,  or  purple. 

ORDER   PENNATULACEA 

SEA-PENS 

These  singular  colonies  resemble  quill-feathers,  such  as  are 
used  for  pens,  and  are  named  for  this  reason.  The  long,  horny 
central  axis  is  naked  below,  and  is  partly  buried  in  the  sand,  but 
is  not  permanently  attached.  The  upper  portion  of  the  axis  has 
two  rows  of  short,  opposite,  lateral  branches ;  on  the  upper  side 
of  the  branches  the  polyps  live  in  separate  inclosures.  Spicules 
of  lime  are  present  in  the  substance  of  the  branches,  which  gives 
them  stability.  Sea-pens  are  found  at  moderate  depths  and  are 
widely  distributed.     They  are  highly  colored  and  phosphorescent. 


TABLE  SHOWING  THE   CLASSIFICATION  OF  THE  CTENOPHORA 
DESCRIBED  IN  THIS  CHAPTER 

Class 
CTENOPHORA 


Orders 

CYDIPPIDA 

(Two  tentacles,  retractile  into 
sheaths) 

LOBATA 

(Numerous  lateral  tentacles 
contained  in  a  groove ;  body 
compressed;  two  large  oral 
lobes) 

CESTIDA 

(Ribbon-like  form,  from  body 
being  extremely  compressed 
in  the  vertical  plane) 

BEBOIDA 

(No  tentacles;  mouth  very 
wide ;  gullet  occupies  greater 
part  of  body) 


Genera 
Pleurohrachia 

Bolina 
Mnemiopsis 

Idyia 


Species 
J*,  rhododaciyla 

B,  alata 

B,  septentrionalis 

B,  vitrea 
M.  Leidyii 

C,  veneris 


I,  roseola 
I,  cyanthina 


154 


CLASS  CTENOPHORA 

COMB-JELLIES 

THESE  are  delicate,  free-swimming,  generally  spherical 
bodies,  resembling  jellyfishes  in  outline,  transparency,  and 
gelatinous  consistency,  but  differing  from  them  widely  in  the 
manner  of  locomotion.  They  are  called  ^' comb-jellies "  from 
the  rows  of  flat  cilia,  arranged  like  the  teeth  of  a  comb,  which 
run  in  eight  meridional  lines  over  the  surface.  It  is  by  means  of 
these  cilia  that  the  animal  moves  through  the  water.  The  little 
paddles  are  worked  in  unison,  in  single  lines,  or  each  one  of  them 
can  be  moved  independently,  and  they  give  the  animal  varying 
and  peculiar  motions.  The  CtenopJiora  are  nearly  transparent, 
but  have  a  prismatic  coloring,  caused  by  the  waving  cilia,  and  at 
night  they  are  phosphorescent.  They  are  widely  distributed, 
being  found  in  all  seas. 

The  mouth  of  the  animal  opens  into  a  gullet  which  extends 
two  thirds  through  the  length  of  the  body.  On  each  side  of  the 
gullet  is  a  vertical  tube.  The  two  tubes  unite  at  the  base  of  the 
gullet,  and  from  there  run  as  a  single  canal  to  the  end  opposite 
the  mouth,  and  open  to  the  outside  through  two  excretor}^  pores. 
From  the  base  of  the  gullet,  where  the  tubes  unite,  two  other 
tubes  extend  laterally,  which  divide  and  subdivide  in  a  horizontal 
plane,  becoming  eight  in  number,  and  connect  at  the  surface  with 
the  lines  of  cilia ;  then,  dividing,  run  in  opposite  directions  to  the 
poles  of  the  spherical  body.  The  animal  derives  its  nourishment 
and  air  through  this  circulatory  system.  A  nervous  system  is 
situated  at  the  pole  opposite  the  mouth,  in  a  small  area  surrounded 
by  cilia ,  in  the  center  is  an  eye-speck,  or  lithocyst. 

155 


156 


MARINE  INVERTEBRATES 


ORDER   CYDIPPIDA 


Fleurobrachia  rhododactyla,  in  motion. 


Genus  Pleurobrachia 

P.  rhododactyla, 

A  transparent  spher- 
ical body,  one  inch  to 
one  and  a  half  inches 
in  diameter,  with 
eight  combs  or  plates 
of  flat  cilia  extending 
from  pole  to  pole. 
At  one  pole  is  the 
mouth,  hke  a  slit,  at 
the  other  a  small  area 
in  the  center  of  which 
is  an  eye-spot.  From 
the  body  hang  two 
tentacles,  half  a  yard 
or  more  in  length, 
fringed  with  cilia. 
The  tentacles  are 
very  contractile  and 
can  be  roUed  up  or 
expanded  with  great 
rapidity;  they  take 
graceful  curves  as  the 

animal  moves  rapidly  through  the  water.     Fleurobrachia  has  a  pink  tint, 

and  prismatic  colors  play  over  it  from  the  vibrating  cilia.     It  is  a  beautiful 

and  interesting  creature  to  watch.      Found 

along  the  shores  of  Massachusetts  and  Maine. 


ORDER  LOBATA 

Genus  Bolina 

IB,  alata.  Slightly  oval  in  form ;  lower 
part  of  the  body  divided  into  two  large  lobes 
which  hang  below  the  mouth.  Four  of  the 
swimming-plates  are  shorter  than  the  other 
four  and  terminate  in  curious  processes  or 
short  appendages  called  auricles.  Bolina  is 
about  two  inches  in  length,  and  is  very 
delicate,  transparent,  and  phosphorescent. 
Its  contractile  power  enables  it  to  vary  in 
outline  to  a  considerable  extent.  It  has  a 
slow  undulating  motion,  and  sometimes 
carries  its  lobes  uppermost  and  open.  Usu- 
ally found  associated  with  Pleurohrachia  from  Massachusetts  northward. 

B,  septentrionalis.    Found  on  the  northern  Pacific  coast. 

B,  vitrea,    A  species  found  in  Florida. 


Bolina  alata,  seen  from  the  broad 
side :  o,  eye-speck  ;  m,  moutli ;  r,  au- 
ricles ;  V,  digestive  cavity ;  gr,  h,  short 
rows  of  flappers ;  a,  /,  long  rows  of 
flappers  ;  b,  n,  x,  t,  z,  tubes  winding  in 
the  larger  lobes;  i,  base  of  gullet. 
About  half  natui-al  size. 


COMB-JELLIES 


157 


GrENus  Mnemiopsis 

M.  Leidyii.  Resembles  Bolina  in  general  form ;  often  six  to  eight 
inches  in  length  j  gregarious,  thousands  often  being  collected  together  5 
exceedingly  phosphorescent. 

ORDER  CESTIDA 

Genus  Cestum 

C.  veneris,  Venus's  girdle.  This  singular  animal,  although  not  an 
inhabitant  of  our  seas,  has  its  place  in  this  group,  and  is  shown  here 
because  of  its  very  curious  shape.  In  form  it  is  flat  and  ribbon-like. 
Sometimes  it  attains  a  length  of  five  feet,  while  in  breadth  it  is  but  one 
or  two  inches.  The  mouth  is  midway  in  its  length  and  is  opposite  the 
sense-organ  or  eye-spot.  On  each  side  of  the  mouth  is  a  short  tentacle 
which  protrudes  from  a  sac.  Four  of  the  swimming-plates  are  small ; 
the  other  four  extend  along  the  edge  of  the  body.  Cestum  icroyq^  by 
contractions  of  the  body  more  than  by  the  combs  which  fringe  its  edges. 
It  is  very  transparent,  with  a  violet  hue,  and  is  so  delicate  that  it  is  diffi- 
cult to  capture  it  uninjured.  Its  habitat  is  the  Mediterranean  Sea.  It 
may  be  seen  among  the  zoological  specimens  in  almost  any  museum. 

ORDER  BEROiDA 

Genus  Idyia 

I,  roseola.  This  species  has  an  ovate  body  three  to  four  inches  in 
height  and  about  half  as  broad.     Some  individuals  are  larger.     It  has 


Ce&twm  veneris. 


158 


MARINE  INVERTEBRATES 


an  eye-spot  on  tlie  upper  rounded  side,  and  at  the  other  end  a  very- 
large  mouth  opening  into  a  digestive  cavity,  which  occupies  the  greater 
part  of  the  body.  A  dehcate  fringe  surrounds  the 
area  about  the  eye-spot,  and  eight  rows  of  cilia  run 
from  there  to  the  oral  end.  It  has  no  tentacles.  Idyia 
is  pink  and  especially  highly  colored  at  the  spawning- 
time.  Like  other  jellyfishes,  their  part  in  life  is  fin- 
ished when  they  have  discharged  their  spawn,  and  the 
first  September  storms  break  them  to  pieces.  In  July 
and  August  they  are  plentiful  on  the  New  England 
coast.  They  appear  at  the  surface  of  the  water  in 
the  hottest  part  of  the  day,  but  disappear  entirely 
when  the  water  is  in  the  least  rough  or  the  weather  is 
cold  or  the  sun  overcast.  Their  movements  are  slow 
and  graceful,  the  long  axis  being  carried  in  a  nearly 
horizontal  position.  They  are  exceedingly  voracious, 
feeding  chiefly  on  other  Ctenophora,  and  often  swal- 
lowing animals  as  large  as  themselves. 
I,  cyanthina.  This  species,  found  on  the  north- 
ern Pacific  coast,  broadens  near  the  center,  making  it  somewhat  vase- 
shaped.  Idyopsis  Clarkii,  a  similar  genus,  found  in  Florida,  is  globular. 
All  these  species  are  very  beautiful,  the  rapid  movement  of  the  cilia  giving 
them  a  brUliant  iridescence. 


Idyia  roseola,  half  nat- 
ural size :  d,  e,  f,  g,  h,  rows 
of  locomotive  flappers. 


^ 


III 

WORMS 
(PLATYHELMINTHES 
NEMATHELMINTHES 
ANNULATA) 


TABLE  SHOWma  THE  CLASSIFICATION  OF  THE  WORMS 
DESCRIBED   IN   THIS  CHAPTER 

Phylum 

PLATYHELMINTHES 

Class 
TURBELLARIA 


Orders 
POLYCLADIDA 

TBICLADIDA 
BHABDOC(£LIDA 


Genera 
JPlanocera 
Stylocliopsis 
Leptoplana 
Planaria 
Procerodes 

Bdelloura 

Fovia 

Class 
TREMATODA 

(External  and  internal  parasites  ) 
Class 

CESTODA 

(Internal  parasites) 
Class 

NEMERTINEA 
Tetrastemma 
Neniertes 

Meckelia 

Cerebratulus 

CosmocepJiala 

JPolina 

160 


Species 

-P.  nebulosa 
S,  Uttoralis 
L.  folium 
I*,  grisea 
jP.  frequens 
B,  rustica 
JB,  Candida 
F,  Warrenii 


T,  arenicola 
K.  socialis 
W.  viridis 
M,  ingens 
M,  rosea 
C.  angulatus 
C.  ochracea 
P,  glutinosa 


WORMS 


161 


Phylum 

NEMATHELMINTHES 

Class 
NEMATODA 

Genus 
Pontonema 


Species 
P,  marinum 


Orders 
EBBANIIA 


Families 

SYLLIDiE 


Phylum 

ANNULATA 

Class 

CH^TOPODA 

Subclass 
Polychseta 

Genera 


rjPolynoe 

APHEODIIIHiE     ]  j^„^„,„thoe 

\  Aphrodite 

PHYLLODOCIDffi         PliyllodOCe 

NEREiDiE       Nereis 


NEPHTHYDIDJE  NephtJiyS 


Marphysa 
Diopatra 
Arabella 
lAimhriconeveis 

Glycera 


EUNICIDJE 
GLYCERIDiE 

SEDENTARIA  or  TUBICOLA 

SPIONIDJE 
CIRRATULIDJE 

TEREBELLID^ 
11 


Nerine 

Cirratulus 

Thelepsus 

Atnphitrite 

Polycirrus 

.  Chcetobranchus 


{ 


Species 

P.  squamata 

JP.  sublevis 

EL.  imbricata 

A,  aculeata 

P,  gracilis 

N.  virens 

N,  pelagica 

N,  limbata 

N,  ingens 

N,  picta 

M.  sanguinea 

D,  cuprea 

A,  opalina 

L,  tenuis 

6r.  ainericana 

G,  dibranchiata 


( N.  agilis 

\  N,  coniocephala 
C,  grandis 
T,  cincinnatus 
A,  ornata 
P,  eximius 
C  sanguineus 


162 


MARINE   INVERTEBRATES 


Orders  Families 

AMPHICTENID^ 
MALDANID^ 

ARENICOLIDiE 
SABELLIB^ 

SERPULIDJE 


SIFUNCTJLOIDEA 


Genera 

Cistenides 
(  Clymenella 
\  Maldane 

Arenicola 

Sabella 
(  Serpula 
\  Spirorhis 

Subclass 
Oligochaeta 

(Mostly  terrestrial  or  fresh-water  forms) 
Class 

GEPHYREA 

J  Sipunculus 
\  JPhascolosoma 

Class 
HIRUDINEA 

(Leeches) 


Species 
C.  Gouldii 
C.  torquata 
M,  elongata 
A.  marina 
S,  microphthalma 
S*  dianthus 
S,  borealis 


S,  nudus 
P,  Gouldii 


WORMS 

BURROWING-  in  sand  and  mud,  lying  under  stones  and  in 
crevices  of  rocks,  concealed  in  various  kinds  of  tubular  cases 
which  are  free  or  attached  to  stones  or  shells,  crawling  over  the 
ground  or  seaweeds,  swimming  free  or  attached  to  other  ani- 
mals, is  found  in  abundance  a  class  of  animals  commonly  known 
as  ''  worms,"  and  generally  regarded  as  repulsive  creatures  un- 
worthy of  attention. 

To  the  biologist,  however,  worms  are  among  the  most  interest- 
ing forms  of  lower  animal  life.  The  amateur  collector,  if  he 
stops  to  give  them  careful  consideration,  will  probably  find  them 
unexpectedly  interesting,  and  will  be  surprised  to  find  how  many 
varieties  of  them  there  are,  and  how  different  they  are  from  his 
preconceived  notion,  of  them.  Worms  are  varied  in  structure, 
their  habits  are  strange,  and  their  form  and  color  often  beautiful. 
Although  plentiful,  they  are  not  conspicuous,  but  are  easily  found 
if  search  is  made  for  them,  and  so  large  a  class  of  shore  animals 
should  not  be  passed  by  unnoticed.  Unusual  biological  interest 
is  attached  to  this  group  because,  in  the  different  types,  affinities 
with  other  classes  of  animals  are  found,  suggesting,  perhaps, 
connecting-links  with  higher  organizations.  They  are  the  first 
animals  to  show  definite  bilateral  symmetry,  or  two  similar  sides, 
and  to  carry  the  same  part  of  the  body  always  in  front.  Formerly 
one  division,  called  Vermes,  comprised  all  the  worms.  To-day  they 
are  separated  into  four  divisions,  or  phyla.  The  most  careless 
observer  easily  recognizes  the  basis  of  separation,  for  the  flat- 
worms,  the  round-  or  threadworms,  the  wheel-like  animalcules, 
and  the  jointed  worms  have  very  obvious  differences.  The  names 
given    the  phyla    express    these    distinctions,  the  termination 

163 


164  MARINE  INVERTEBRATES 

meaning  "  worm " ;  the  prefixes  Platy-,  N'emat-,  Troc-,  meaning 
''flat/'  '^  thread/'  '' wheel/' respectively ;  while  Annulata,  meaning 
"  ringed/'  describes  the  segmented  forms  belonging  to  that 
phylum. 

There  are  vast  numbers  of  parasitic  worms,  which  live  inter- 
nally or  externally  on  their  hosts,  there  being  no  animal  of  land 
or  sea,  of  high  or  low  degree,  which  is  not  subject  to  the  afliction 
of  these  visitors.  The  parasitic  worms  are  degenerate,  some 
being  without  digestive  organs,  or  without  eyes,  or  without  loco- 
motor organs,  and  so  on,  as  the  case  may  be,  the  host  supply- 
ing the  missing  function.  The  life-history  of  these  low  forms 
is  interesting ;  but  parasitic  worms  do  not  come  within  the  scope 
of  this  book,  and  are  mentioned  only  to  mark  their  place  in  the 
series. 

PHYLUM    PLATYHELMINTHES 

FLATWORMS 

The  flatworms  have  a  flattened  body,  more  or  less  compressed 
in  the  different  classes.  Ordinarily  the  body  is  very  thin,  and, 
when  short,  has  a  leaf -like  form;  when  long  it  is  ribbon-like. 
Some  species  are  thick  in  the  middle  and  thin  at  the  edges.  They 
have  a  dorsal,  or  upper,  and  a  ventral,  or  under,  surface  j  a  right 
and  a  left  side ;  an  anterior  and  a  posterior  end„  The  anterior 
end  is  carried  forward  and  has  some  of  the  characteristics  of  a 
head,  though  a  distinct  head  is  not  apparent.  The  mouth  is  on 
the  ventral  surface.  In  some  species  it  is  in  the  middle  of  the 
length  of  the  body ;  in  others  it  is  before  or  behind  this  point. 

The  flatworms  are  the  first  animals  to  assume  pronounced 
bilateral  symmetry.  They  are  soft-bodied,  having  no  supporting 
skeleton,  and  they  have  no  segments,  or  divisions,  such  as  are 
found  in  higher  types,  as  in  Annulata.  They  have  no  body-cavity, 
the  space  between  the  organs  and  the  body- wall  being  filled  with 
tissue.  The  alimentary  canal  has  no  anal  aperture,  the  excretions 
being  carried  off  by  a  water-vascular  system  consisting  of  branch- 
ing vessels  which  end  in  minute  bundles  of  vibrating  cilia,  called 
ciliary  flames.  These  flames  communicate  with  the  exterior 
through  small  pores  or  flame-cells.     Their  sense-organs  are  eyes 


WORMS  165 

and  otocysts.  The  latter  are  sacs  containing  crystals  of  carbo- 
nate of  lime,  and  their  function  is  supposed  to  be  that  of  hearing. 
The  flatworms  are  hermaphroditic,  and  their  propagation  is  by 
means  of  eggs.  They  are  numerous  and  very  generally  distrib- 
uted, occurring  in  fresh  and  salt  water,  on  land  and  shore,  on 
the  surface  and  in  the  depths  of  the  sea.  A  vast  number  also  are 
parasites  and  infest,  internally  or  externally,  nearly  every  living 
creature.  The  parasitic  forms  differ  anatomically  from  the  free- 
living  worms.  The  internal  parasites,  living  by  absorption  of  the 
digested  food  of  their  hosts,  have  no  digestive  organs  5  they  are 
also  devoid  of  organs  of  sense  and  of  defense.  The  external 
parasites,  being  carried  about  by  their  hosts,  are  without  organs 
of  locomotion. 

CLASS   TURBELLARIA 

The  turbellarians  are  the  simplest  group  of  bilateral  animals 
and  occupy  the  lowest  place  among  worms.  They  owe  their 
name  to  the  fact  that  they  are  covered  with  cilia,  which  are  con- 
stantly in  motion  and  cause  a  slight  turbulence  in  the  water 
around  them. 

ORDER   POLYCLADIDA 

(^^Many-branched  "^ 

The  polyclads  are  found  below  half -tide  mark  on  the  under  side 
of  stones  and  on  seaweeds.  Sometimes  they  are  found  swimming 
about  at  night.  They  are  leaf -like  in  form,  one  inch  to  two  inches 
in  length,  and  are  very  thin  and  delicate.  They  adapt  themselves 
to  the  inequalities  of  the  surfaces  to  which  they  attach  them- 
selves, and  often  are  of  the  same  color,  and  therefore  are  so  incon- 
spicuous that  they  are  apt  to  escape  notice.  They  move  with  a 
gliding  motion  over  surfaces,  and  often  swim  when  in  search  of 
food. 

The  intestine  is  much  branched  and  has  no  anal  aperture. 
From  the  mouth,  which  is  placed  in  the  center  of  the  ventral  sur- 
face, a  pharynx,  or  muscular  fold,  is  protruded  in  some  species, 
which  enables  the  worm  to  attach  itself  to  and  consume  prey  of 
considerable  size.      After   digestion  has   taken  place,  the  fecal 


166  MARINE  INVERTEBRATES 

matter  collects  in  tlie  main  intestine  and  is  forcibly  ejected  by 
the  pharynx.  Numerous  eyes  are  collected  in  groups  on  the 
anterior  dorsal  surface,  or  arranged  around  the  margin  of  the 
body.  The  eggs  are  laid  in  shell-like  cases,  and  cemented 
together'in  plate-like  masses  or  in  spirals,  and  attached  to  shells 
or  stones.     (Plate  XL VIII.) 

Genus  JPlanocera 

JP.  nebulosa.  One  half  of  an  inch  wide  and  three  quarters  of  an  inch 
long,  circular  or  elliptical  in  shape  ;  very  flat  and  thin ;  olive-green 
on  the  dorsal  surface,  with  a  line  of  darker  color  on  the  posterior  end, 
and  whitish  retractile  tentacles  on  the  back.  Found  creeping  on  under 
side  of  stones  in  tide-pools. 

Genus  Stylochopsis 

S,  littoralis.  About  one  half  of  an  inch  long ;  changeable  in  form, 
from  broad  oval  to  elliptical )  color  pale  green,  veined  with  a  lighter  shade 
on  the  dorsal  side,  flesh-colored  on  the  ventral  surface ;  numerous  eyes  ar- 
ranged in  irregular  rows  near  the  margin  and  in  groups  in  front  of  the 
tentacles,  also  clusters  of  eyes  on  the  tentacles.  Found  under  stones 
between  tide-marks. 

Genus  Leptoplana 

i.  folium.  Body  flat ;  margin  thin  and  undulated ;  shape  leaf -like, 
but  changeable ;  about  one  inch  long  and  one  half  of  an  inch  wide  5  color 
pale  yellow,  veined  with  a  deeper  shade ;  eyes  in  four  groups  near  the 
anterior  end. 

ORDER  TRICLADIDA 

C ' '  Three-branched ' '  ) 

The  triclads  are  divided  into  three  groups :  those  of  the  fresh- 
water ponds  and  streams,  those  of  the  land  and  sea,  known  as 
planarians,  and  those  of  the  sea.  The  planarians  are  the  most 
interesting  worms  in  the  order.  The  triclads  differ  from  the 
polyclads  in  being  elongate  in  form  and  in  having  the  intestine 
in  three  branches  instead  of  in  many.  The  mouth  is  midway  in 
the  length  of  the  body,  on  the  ventral  side,  and  from  it  protrudes 
a  pharynx,  which  is  cylindrical  or  bell-shaped,  and  is  capable  of 
great  dilatation.  With  the  pharynx  the  worm,  which  is  wholly 
carnivorous,  envelops  other  worms,  crustaceans,  or  any  animal 
food.  Several  species  are  found  on  the  under  side  of  stones  in 
tide-pools. 


PLATE    XL VIII. 


Polyclad  worm. 
Worm-tubes  of  Diopatra. 


WORMS  167 

Genus  JPlanaria 

P,  grisea.  Oval  or  elliptical  in  form ;  anterior  end  truncate  :  poste- 
rior end  rounded ;  color  yellow  or  gray,  with  a  light  stripe ;  two  black 
eyes  surrounded  with  white ;  length  one  half  to  three  quarters  of  an 
inch ;  width  about  one  eighth  of  an  inch.  Found  under  stones  between 
tide-marks. 

Genus  JProcerodes 

p.  frequens.  One  eighth  of  an  inch  long;  brown  or  black  above, 
gray  below ;  has  two  kidney-shaped  eyes ;  active  and  abundant.  Found 
under  stones  near  high -water  mark. 

Genus  Bdelloura 

p.  rustica.    Body  milk-white,  smooth,  thin.    Found  on  JJlva  latissima 
(sea-lettuce). 
B,  Candida,    Parasitic  on  the  gills  of  the  horseshoe- crab. 

Genus  IPovia 

F,  Warrenii,    Bright  red,  narrow,  oblong.    Found  on  eel-grass. 

ORDER  RHABDOCCELIDA 

Minute,  active  worms  found  among  the  red  seaweeds.  They 
are  brown  in  color,  and  are  marked  by  one  or  more  transverse 
white  bars. 

CLASS  NEMERTINEA 

The  nemerteans  are  long,  narrow,  flat,  smooth  worms,  and 
vary  from  one  half  of  an  inch  to  many  feet  in  length.  They  are 
exceedingly  contractile,  and  when  alarmed  can  shrink  to  less  than 
half  their  normal  length.  They  are  very  generally  distributed, 
and  are  to  be  found  between  tide-marks,  in  loose  coils  like  a 
string,  under  stones  on  sandy  and  muddy  shores.  The  very 
long  species,  like  Lineus  marinus,  are  solitary,  bat  other  smaller 
species  are  gregarious,  many  worms  being  coiled  together  in 
tangled  masses.  Some  species  are  to  be  found  in  empty  shells, 
and  others  live  among  the  seaweeds.  They  are  very  slimy,  the 
epidermis  secreting  an  abundance  of  mucus,  and  they  can  often 
be  tracked  by  the  trail  of  slime  they  leave  behind  them.  This 
mucus  sometimes   hardens,  forming  for  some  species  a  tubu- 


168  MARINE  INVERTEBRATES 

lar  covering ;  others  remain  naked.  AU  are  covered  with  vibrat- 
ing cilia,  which  is  a  "universal  feature  of  flatworms.  In  color 
they  may  be  white,  yellow,  green,  red,  purple,  etc.,  and  some- 
times they  are  banded  or  striped  with  a  contrasting  color.  The 
ventral  is  usually  lighter  than  the  dorsal  surface. 

The  principal  characteristic  of  the  nemertean  worms  is  a  long 
thread-like  organ,  known  as  the  proboscis.  This  lies  in  a  sheath 
along  the  center  of  the  dorsal  surface,  and  is  quickly  thrown 
out  to  a  great  length,  and  as  quickly  completely  withdrawn  within 
the  body.  The  proboscis  is  slender,  hollow,  muscular,  and  fuU 
of  nerves.  It  reaches  the  outside  through  a  pore  at  the  ante- 
rior end  of  the  body,  and  has  no  connection  with  the  alimen- 
tary system.  It  is  used  as  a  feeler  and  as  a  weapon.  Some 
species  have  a  sharp  spine  at  the  end  of  the  proboscis,  others 
have  stinging-cells.  The  proboscis  is  sometimes  so  forcibly 
ejected  that  it  breaks  off,  in  which  case  it  retains  its  vitality  for 
some  time,  and  seems  as  if  it  were  itself  a  worm.  A  new  pro- 
boscis is  quickly  grown  by  the  worm  to  take  the  place  of  a  lost 
one.  The  head  is  a  little  broader  than  the  body,  and  has  eyes 
arranged  in  one  or  several  pairs  on  each  side.  The  mouth  is  on 
the  ventral  surface,  near  the  anterior  end,  has  thick  lips,  and  is 
very  dilatable.  Through  the  mouth  the  animal  ejects  a  part  of 
the  esophagus  and  envelops  its  prey,  which  is  often  of  consider- 
able size.  Chgetopod  worms  they  often  swallow  whole ;  the  soft 
parts,  after  being  digested,  are  carried  off  through  the  regular 
passages,  ending  in  the  ciliary  flames  (page  164),  while  the  indi- 
gestible parts  are  ejected  at  the  anus.  Often  the  spines  and 
bristles  find  their  way  out  by  perforating  the  intestine  and  the 
body-wall,  without  apparently  doing  the  worm  any  injury.  The 
perforated  parts  quickly  heal. 

These  worms  have  the  strange  power  of  regenerating  lost  parts ; 
mutilated  portions  are  soon  repaired.  The  anterior  end,  when 
severed  from  the  rest  of  the  body,  grows  again  into  a  complete 
individual,  while  the  posterior  end  continues  to  perform  part  of 
its  functions  and  retains  its  vitality  for  a  considerable  time  be- 
fore dying.  One  species,  Lineus  sanguineus^  is  capable,  after  being 
broken  in  pieces,  of  regenerating  each  section  into  a  perfect  worm. 


WORMS  169 

The  nemerteans  are  carnivorous,  voracious,  and  often  canniba- 
listic. They  will  live  for  some  time  in  confinement,  losing,  how- 
ever, their  bright  color,  and  the  smaller  worms  will  gradually  dis- 
appear, as  they  are  devoured  by  the  larger  ones.  The  mode  of 
locomotion  varies  with  the  order.  Some  species  attach  their  long 
proboscis  to  a  distant  object,  then  drag  the  body  to  it;  some  glide 
rapidly  along  by  means  of  the  muscles  of  the  body  and  the  cilia 
which  cover  it;  others  swim.  The  swimming  forms  have  thin 
edges  which  have  a  wave-like  motion,  and  this,  together  with  a 
lateral  movement  of  the  tail,  propels  them  through  the  water. 
In  some  species  the  worm  develops  directly  from  the  egg ;  others 
pass  through  a  larval  stage  before  reaching  maturity. 

Genus  Tetrastemma 

T,  arenicola.  Dark  flesh-color  or  purplish ;  slender,  cylindrical,  four 
to  five  inches  long  when  extended ;  head  changeable  in  form  and  partly 
distinct  from  body  because  of  slight  constriction  at  the  neck.  It  lives  in 
sand  at  low-water  mark. 

Genus  Nemertes 

N*  socialis.  Individuals  very  slender,  five  to  six  inches  long  when 
extended;  color  brown  or  black,  a  little  hghter  underneath j  three  or 
four  eyes  in  lines  on  each  side  the  head.  It  is  abundant  under  stones  on 
rocky  shores,  many  coiled  together,  forming  large  masses. 

N.  viridis.  Color  olive-green  or  brown,  crossed  by  faint  pale  hues ; 
body  changeable  in  form;  when  extended,  six  to  eight  inches  long,  one 
eighth  of  an  inch  or  less  in  breadth ;  row  of  dark  eyes  on  each  side  of 
flat  head.  Common  under  stones  between  tide-marks  on  northern  rocky 
shores. 

Genus  Meckelia 

M,  ingens.  One  of  the  largest  nemertean  worms ;  found  on  sandy 
and  muddy  shores  near  low-water  mark.  The  young,  from  several  inches 
to  a  foot  long,  are  common.  When  full-grown  some  attain  the  length  of 
twelve  or  thirteen  feet,  and  are  an  inch  in  breadth  and  quite  flat  when 
extended,  but  can  contract  to  two  or  three  feet  in  length,  and  are  then 
nearly  cylindrical.  This  worm,  although  so  soft,  penetrates  the  sand 
with  great  rapidity.  Its  head  changes  shape  constantly  and  assists  the 
proboscis  when  burrowing.  It  is  also  able  to  swim.  Its  color  is  yel- 
lowish or  flesh-color,  with  whitish  edges  and  a  central  band. 

M.  rosea.  The  largest  specimens  are  six  to  eight  inches  long  and 
one  quarter  of  an  inch  broad ;  lives  in  burrows  on  sandy  beaches ;  color 
red  or  pink ;  often  covered  with  sand,  which  adheres  to  the  mucus  which 
the  worm  secretes. 


170  MARINE  INVERTEBRATES 

Genus  Cerebrattilus 

C.  angulcitus.    Olive-green,  with  light  dorsal  stripe. 

Genus  Cosmocephala 

C  ocJiracea,  Two  to  three  inches  long  when  extended ;  gray  or 
yellowish- white,  and  mottled  by  the  internal  organs  showing  through 
the  translucent  body ;  line  of  lighter  color  down  the  back ;  anterior  end 
often  orange-colored.  It  is  common  near  low-water  mark  under  stones 
and  in  the  dead  tubes  of  Serpula. 

Genus  I^olina 

JP,  glutinosa.  One  to  two  inches  long ;  color  orange  or  light  yellow, 
with  a  faint  line  of  deeper  color  down  the  center  of  the  dorsal  surface ; 
very  slimy  -,  eyes  numerous,  in  oblique  lines  on  the  head.  Found  in 
tide-pools  on  algae. 

PHYLUM   NEMATHELMINTHES 

ROUNDWORMS 

The  worms  of  this  phylum  have  the  general  name  of  round- 
worms, which  distinguishes  them  from  the  flatworms  of  the  pre- 
ceding division  and  from  the  segmented  worms  of  the  Anmdata. 
The  body  is  elongated,  cylindrical,  smooth,  and  pointed  at  both 
ends.     With  few  exceptions,  they  are  parasitic. 

A  few  of  the  nematode  species  are  free,  living  under  stones 
and  among  seaweeds  at  about  low-water  mark. 

CLASS  NEMATODA 

Genus  I^ontonema 

P,  marimifn.  Slender,  white,  smooth,  active,  cylindrical;  con- 
stantly coiling  and  uncoiling  itself. 

PHYLUM  ANNULATA 

SEGMENTED  WORMS 

The  name  of  this  phylum  expresses  the  principal  characteristic 
of  the  group  of  worms  which  have  elongated  bodies  composed 
of  series  of  short  parts,  or  ring-like  divisions.  Each  one  of  these 
segments  contains  a  separate  and  similar  set  of  internal  organs. 


WORMS 


171 


The  annelids  are  divided  into  four  classes,  one  of  which,  the 
Gephyrea,  has  not  the  characteristics  which  distinguish  the  group. 
The  classes  are  easily  recognized  by  conspicuous  features.  Some 
have  bristles ;  others  have  scales ;  others  have  tentacles  around 
the  head  and  inclose  themselves  in  tubes.  Many  are  highly 
colored,  and  all  are  of  great  interest  to  the  naturalist  from  the 
diversity  of  their  habits,  form,  and  structure,  and  from  the  analo- 
gies they  bear  to  other  and  higher  types  of  animals. 

The  annelids  are  the  highest  type  of  worms,  their  organs 
having  attained  more  special  functions.  The  sense-organs  of  eye 
and  ear  are  more  developed,  and  the  nervous  system  has  distinct 
centers,  or  ganglia,  the  first  and  largest  ganglion  being  a  part  of 
the  head.  They  are  found  in  abundance  everywhere.  Some 
species  grow  to  the  length  of  one  foot  or  two  feet.  Some  are 
carnivorous,  others  vegetarian,  and  many  are  mud-eaters,  swal- 
lowing sand  and  mud  for  the  sake  of  the  organisms  they  con- 
tain. They  themselves  are  food  for  fishes,  which  devour  them 
in  vast  quantities,  rooting  them  out  of  their  burrows  or  cap- 
turing them  at  night,  at  which  time  they  swim  about. 


CLASS   CHiETOPODA 

('"  Bristle-footed  "^ 

The  bristle-worms.  This  class  of  worms  has  bunches  of  bristles 
on  both  sides  of  each  segment  of  the  body,  which  serve  as  organs 
of  locomotion,  or  bristle-feet. 
The  bristles  emanate  from 
outgrowths  of  the  body 
known  as  pmrqwdia,  which 
are  practically  limbs.  The 
parapodia  are  sometimes 
divided  into  distinct  lobes 
or  branches.  The  bristles 
are  of  various  shapes  and 
often  of  brilliant  color.  They 
are  usually  horny,  sometimes 
simple,  sometimes  divided  into  joints,  and  vary  in  shape  in  different 
genera.     The  parapodia  have,  besides  the  bristles,  a  second  set  of 


veni.cirr 


A  magnified  parapodinm  of  Nereis  clumerilii :  dors, 
cirr,,  dorsal  cirrus  ;  ve7it.  cirr.,  ventral  ciiTus  ;  s,  setae. 


172  MARINE  INVERTEBRATES 

hair-like  appendages,  called  cirri.  These  are  sense-organs  and  also 
have  a  respiratory  function.  The  cirri  too  vary  in  shape  in  dif- 
ferent genera.  Generally  they  are  hair-like,  but  sometimes  con- 
ical ;  again  they  are  broadened  into  scales,  as  in  the  ApJiroditidm. 

The  body-cavity  in  cheetopod  worms  is  divided  into  a  series  of 
chambers  or  segments.  These  divisions  seem  on  the  exterior  like 
constrictions,  and  give  the  body  the  appearance  of  a  series  of  rings. 
The  internal  organs  are  repeated  in  each  segment,  so  that  each  of 
the  latter  contains  a  portion  of  the  alimentary  canal,  a  pair  of 
nephridia,  a  pair  of  nerve-ganglia,  and  blood-vessels  which  connect 
the  main  blood-vessels  running  along  the  dorsal  and  ventral  sur- 
faces. The  alimentary  canal  runs  through  the  body,  but  is  con- 
stricted at  each  joint.  The  nephridia  are  curved  tubes,  which 
are  excretory  organs,  opening  to  the  outside  and  carrying  off 
the  waste  products  which  have  passed  into  the  fluid  of  the  body- 
cavity. 

The  chsetopod  worms  have  a  well-developed  nervous  system, 
beginning  with  a  two-lobed  ganglion  forming  a  brain  and  head, 
then  extending  through  the  worm  in  a  double  ventral  chain  and 
series  of  ganglia.  They  have  also  a  blood- vascular  system.  The 
blood  is  either  colored  or  colorless.  Sometimes  it  is  a  bright  red 
or  green,  and  is  often  visible  through  the  body-wall.  The  circu- 
lation is  effected,  not  by  means  of  a  heart,  but  by  wave-like  (peri- 
saltic)  contractions  of  the  dorsal  blood-vessel.  The  body  is  cylin- 
drical, but  in  many  cases  is  somewhat  flattened.  There  are  two 
layers  of  muscles,  one  of  which  encircles  the  body,  while  the  other 
extends  parallel  with  its  length.  Respiration  is  effected  by  gills, 
which  may  be  simple,  hair-like  appendages  to  the  parapodia,  or 
branched,  or  comb-like  in  form.  Sometimes  they  are  confined 
to  the  middle  segments,  as  in  Arenicola ;  sometimes  to  the  seg- 
ments near  the  head,  as  in  Tubicola  ;  or  they  may  be  extended 
over  the  whole  dorsal  surface. 

SUBCLASS  POLYCHiETA 

C"  Many -bristled  "^ 

The  polycheete  worms  have  one  or  two  well-developed  parapodia, 
or  limbs,  on  each  side  of  every  segment  of  the  body,  and  on  each 


WORMS  173 

parapodium  is  a  bunch  of  bristles,  or  chmtce.  There  are  hundreds 
of  species  of  this  class  of  worms,  the  species  being  based  on  the 
shape  and  the  lobes  of  the  parapodia,  the  relative  length  of  the  cirri, 
the  form  and  arrangement  of  the  chsetee,  and  so  on.  They  are 
abundant  on  the  shore  everywhere,  but  abound  where  rocks  and 
stones  afford  them  some  shelter.  Many  burrow  in  the  sand  and 
mud.  In  doing  this  the  worm  eats  his  way  into  the  hole,  swal- 
lowing the  mud  and  sand.  He  assimilates  the  organic  or  vege- 
table matter  the  mud  contains,  and  ejects  the  rest  in  cylindrical 
coils,  known  as  castings,  which  lie  in  heaps  at  the  mouth  of  the  bur- 
row.    By  these  castings  they  may  be  traced.    Others  secrete  tubes. 

The  polychaete  worms  are  di^dded  into  Errantia,  which  are 
wandering,  free-swimming  forms,  and  Sedentaria  or  Tubicolaj 
which  live  in  tubes  permanently.  These  distinctions  are  not 
strictly  correct,  since  some  species  of  errant  polychaetes  form 
tubes  {EunicidcB),  and  some  Sedentaria  form  no  tubes. 

Many  potychaetes  are  beautifully  colored,  some  in  vivid  reds 
and  greens,  with  various  markings;  some  are  iridescent;  some 
are  phosphorescent. 

ORDER  ERRANTIA 

Carnivorous,  free  Polychmta,  with  protrusible  pharynx  armed 
with  a  horny  jaw.     ^'  They  are  active,  fierce  beasts  of  prey." 

Family  syllid^ 

This  family  is  the  highest  in  organization  of  the  worms.  They 
are  small,  the  majority  being  less  than  an  inch  in  length,  and 
many  are  minute.  They  are  often  highly  colored.  Many  have 
long  cirri  on  the  feet;  some  have  alternation  of  generation. 
They  are  common  everywhere  along  the  coast,  but  are  not  seen 
unless  searched  for.  Sponges  sometimes  are  alive  with  them. 
They  are  interesting  subjects  for  microscopic  study. 

Family  APHRODiTiD.a: 

The  scale-bearing  annelids.  This  family  of  worms  is  distin- 
guished from  all  others  by  having  scales  on  the  back.  The  scales, 
called  elytra,  are  flattened  dorsal  cirri  carried  on  the  upper  para- 


174  MARINE   INVERTEBRATES 

podia,  and  generally  on  alternate  segments  and  in  a  double  row 
down  the  back.  The  elytra  are  the  breathing-organs,  and,  although 
of  a  horny  texture,  are  richly  supplied  with  nerves.  The  worms 
are  short  and  have  a  large  protrusible  pharynx  armed  with  a 
double  pair  of  horny  jaws. 


Genus  JPolynoe 

The  species  of  Polynoe  are  determined  by  the 
number  of  scales  they  bear.  They  have  a  flattened 
short  body  with  nearly  parallel  sides.  The  bristles 
are  of  a  bright  golden  color.  The  proboscis  is  large 
and  has  four  powerful  jaws  at  the  end  and  a  circle  of 
papillae  at  the  top.  They  are  sluggish  in  movement 
and  are  found  under  stones  and  in  the  crevices  of  rocks. 
When  disturbed  they  roll  themselves  into  a  ball. 

JP,  squamata.  Twelve  pairs  of  rough  scales ;  color 
sandy-brown,  speckled  j  one  inch  to  one  and  a  half 
inches  long ;  the  broad,  oval  scales  overlap  and  entirely 
cover  the  body  and  head.  Some  Polynoe  when  disturbed 
throw  off  every  scale.  Very  common  north  of  Cape  Cod. 
JP.  sublevis.  Twelve  pairs  of  smooth  scales ;  usually 
grayish-brown  in  color,  speckled  with  dark  spots ;  iri- 
descent; last  pair  of  scales  more  slender  than  the  others ; 
Polynoe  squamata.  length  oue  and  a  quarter  inches,  breadth  about  one 
quarter  of  an  inch. 


Genus  Harmothoe 

H,  imhricata.  Sixteen  pairs  of  smooth  scales ;  variable  in  color ; 
usually  gray,  speckled,  or  striped. 

Genus  Aphrodite 

A,  aculeata.  This  polychsete,  sometimes  called  the  sea-mouse,  is  one 
of  the  most  beautiful  of  worms.  It  is  brightly  iridescent  in  color,  from 
its  setsB,  which  form  *a  fur-like  eoating  over  the  dorsal  surface.  It  has 
fifteen  pairs  of  scales,  but  they  are  hidden  by  the  numerous  setae.  These 
bristles  cover  its  sides  and  back.  Some  are  coarse  and  nearly  an  inch 
long,  with  sharp  points,  and  are  barbed  near  the  ends.  They  curve 
over  the  back  like  the  quills  of  a  porcupine.  The  body  is  three  to  six 
inches  long.  It  is  broadest  in  the  middle  and  tapers  to  a  point.  They 
live  in  mud  below  tide-mark,  and  may  be  found  washed  upon  the  beach 
after  storms. 


WORMS 


175 


Family  phyllodocid^ 

These  animals  are  commonly 
known  as  "  paddle- worms/'  on 
account  of  having  leaf-Kke  cirri, 
which  they  use  in  locomotion. 
The  head  is  long  and  bears  four 
pairs  of  short  and  four  pairs  of 
long  tentacles.  The  body  is  long 
and  depressed,  sometimes  two 
feet  in  length,  usually  eight  to 
twelve  inches  long.  The  general 
color  is  bright  green  and  irides- 
cent. Found  in  tide-pools.  Speci- 
mens are  often  found  by  digging 
in  sandy  mud,  or  they  may  be 
obtained  by  placing  old  shells 
and  other  material  in  a  dish  of 
sea-water.  When  the  water  be- 
comes a  little  stale,  the  worms  of 
this  and  otherf amilies  make  their 
way  to  the  sides  of  the  dish,  where 
they  secrete  a  colorless  slime 
w^hich  holds  mud  or  any  light 
matter  that  it  may  come  in  con- 
tact with.  In  this  condition,  when  lifted  or  disturbed,  they  crawl 
rapidly  out  of  the  slime,  and  show  to  good  advantage  their  elongate 
body,  which  is  often  beautifully  colored. 

Genus  Phyllodoce 

JP,  gracilis.     Three  inches  or  more  long  and  one  sixteenth  of  an  inch 
wide ;  large  proboscis,  with  twelve  longitudinal  rows  of  prominent  pro- 


Aphrodite  aculeata,  natural  size  :  c,  neuropodial 
chaetae;  p,  palps;  1,  iridescent  bristles;  2,  stiff 
chsetae ;  3,  f eltiug  bristles  of  notopodium. 


176  MARINE  INVERTEBRATES 

jections  on  the  swollen  base,  its  terminal  end  smooth,  with  a  circle  of 
round  projections  at  the  orifice ;  color  green,  with  a  row  of  dark  spots 
down  the  center  of  the  dorsal  surface  and  a  fainter  line  of  spots  on  each 
side  at  the  base  of  the  parapodia.    Found  on  the  New  England  coast. 


Family  nereides 

GrENus  Nereis 

Among  the  most  common  of  the  polychaete  worms  is  the  genus 
Nereis,  various  species  of  which  are  found  in  all  parts  of  the 
world.  They  are  abundant  under  stones,  among  seaweeds,  and 
living  in  burrows  between  tide-marks.  They  are  active,  fierce, 
and  voracious.     Some  attain  a  length  of  eighteen  or  more  inches. 

They  are  commonly  known  as  ''clam-worms," 
and  are  used  by  fishermen  for  bait.  Nereis 
has  a  distinct  head,  consisting  of  two  parts. 
One,  the  prostomiimi,  bears  on  its  upper  side 
four  eyes  and  a  pair  of  short,  conical  tentacles, 
and  on  the  lateral  sides  a  second  pair  of  pro- 
cesses called  palps.  The  palps  are  more  con- 
Head  of  Nereis pelagica.  .  ,  ,i         i        i       -i  -i  '    i        j> 

spicuous  than  the  tentacles,  and  consist  or 
two  parts,  a  large  base  and  a  small  terminal  point,  the  latter 
capable  of  being  withdrawn.  The  palps  are  sense-organs  and 
perhaps  test  the  foodo  The  second  part  of  the  head,  or  peristo- 
mium,  bears  on  the  sides  four  pairs  of  long  tentacles  which  are 
used  as  feelers.  The  mouth  is  on  the  ventral  side,  and  through  it 
Nereis  throws  out  its  pharj^nx,  which  contains  a  horny,  notched 
jaw.  It  seizes  its  prey  with  this  jaw,  which,  with  the  pharynx, 
is  then  withdrawn  and  tears  the  food  apart,  acting  like  a  gizzard. 
The  body  of  Nereis  is  rounded  above  and  nearly  flat  beloWo  Each 
of  the  segments  has  a  pair  of  parapodia,  bearing  a  bundle  of  bris- 
tles and  cirri.  The  last  segment  of  the  body  is  elongated,  cylin- 
drical, and  without  parapodia,  but  has  on  the  end  a  pair  of  long 
cirri,  which  give  the  appearance  of  a  divided  tail.  Each  segment 
of  the  body,  except  the  head-  and  tail-segments,  contains  a  pair 
of  excretory  tubes  {nephridia),  ganglia  of  nerves,  and  a  portion  of 
the  intestine  and  of  the  vascular  system.  There  are  circular 
muscles  by  which  the  worm  can  diminish  its  diameter,  longitu- 


WORMS 


177 


Nereis  pelagica.    1,  male  ; 
2,  female. 


dinal  muscles  in  four  bands,  and  muscles  to 
move  the  parapodia.  Breathing  is  carried  on 
over  the  whole  surface  of  the  body,  and  es- 
pecially in  parts  of  the  lobes  of  the  parapodia 
called  gills.  Its  sense-organs  are  eyes,  palps, 
tentacles,  and  cirri. 

W.  virens.  This  species  is  found  from  New 
York  northward  in  muddy  and  shelly  sand,  and 
under  rocks  between  tide-marks,  living  in  burrows, 
which  it  lines  with  a  mucous  secretion.  It  is  very 
active  and  voracious,  feeding  on  other  worms, 
Crustacea,  etc.,  which  it  captures  with  its  horny, 
protruded  jaw.  At  night  it  leaves  its  burrow  and 
swims  freely  about  like  an  eel,  frequently  falling 
a  prey  to  fishes.  In  color  it  is  dull  bluish-green, 
with  some  mdescence.  The  gills,  which  are  leaf- 
like appendages  on  the  parapodia,  are  green  on 
the  anterior  end  of  the  body  and  become  bright 
red  farther  back.  This  species,  and  N.  hranti  of 
Alaska,  are  the  giants  of  polychaete  worms,  often 
measuring  eighteen  inches  or  more  in  length. 
N.  pelagica.    Found  in  abundance  on  the  New  England  shore  and 

northern  coasts  under  stones  and  on  shelly  bot- 
toms.    The  female  is  four  to  five  inches  long, 

while  the  male  is  only  two  inches  in  length.     In 

this  species  the  body  is  widest  in  the  middle, 

while  in  other  species  it  is  widest  at  the  ante- 
rior end.     The  palps  are  long,  and  the  second 

head-piece  (peristomium)  is  twice  as  long  as  the 

next  segment.     The  color  is  reddish-brown  and 

iridescent. 
3r.  Umbata,     Five  to  six  inches  long;  jaws 

light  yellow,  sharp,  and  slender ;  parapodia  and 

bristles  smaUer  on  the   anterior  than   on  the 

posterior  end  -,  color  dark  brown,  with  li^ht  lines 

on  the  sides  and  appendages,  pale  red  on  the 

posterior  end;  dorsal  blood-vessel  apparent,  and 

the  heart-like  pulsations  can  be  distinctly  seen. 

The  male  worm  is  red  in  the  middle  section. 

Found  along  the  middle  Atlantic  coast  on  sandy 

shores. 

Family  nephthydid^ 

In  this  family  the  worms  have  a  long, 
thick,  flattish  body,  a  section  of  which  has 
a  quadrangular  form.  The  lobes  of  the 
parapodia  are  widely  separated  and  fringed 


Nereis  limhata.  Male,  anteriof 
part  of  body,  head  and  extended 
proboscis. 


12 


178 


MARINE  INVERTEBRATES 


■with  membrane,  appearing  like  double  parapodia.     The  pharynx 
is  very  large  and  projected  as  in  Nereis. 


Genus  Nephthys 

N.  ingens.     Sometimes  six  inches  long  and  one  quarter  of  an  inch 
broad ;  usually  smaller  j  color  whitish,  with  red  blood-vessel  showing  on 

dorsal  side;  appendages  dark  blown;  moves 
actively  and  burrows  quickly  into  the  mud; 
when  captured  often  breaks  off  a  portion  of  the 
posterior  end,  which  it  is  able  to  reproduce; 
proboscis  large;  branchiae  between  the  dorsal 
and  ventral  parapodia.  Found  burrowing  in 
all  kinds  of  mud  on  the  New  England  coast. 

JV.  picta.  More  slender  than  N.  ingens  ;  color 
whitish,  mottled  with  brown  on  the  dorsal  an- 
terior end ;  often  a  dark  line  down  the  back ; 
head  square  in  front  and  triangular  in  the  back. 
Found  in  sandy  mud  at  low- water  mark. 


Faivoly  eunicidje 


These  are  beautiful  worms,  having  a  red- 
dish-brown iridescent  body,  with  bright-red 
^^  branching  gills,  which  look  like  feathers, 
f5  along  the  back.    They  form  parchment-like 


<g^5  tubes. 


Genus  Marphysa 


Nephthys  ingens.  Anterior  part 
of  body  and  extended  proboscis  ; 
ventral  view.    Enlarged. 


M,  sanguinea.    Length  six  inches  or  more ; 

color  bronze  or  brownish-red  and  iridescent; 

has  bright-red  branched  gills  and  six  caudal  cirri 
of  different  lengths  ;  body  flattened,  except  at  the  anterior  end,  where  it 
becomes  narrow  and  cyhndrical ;  has  powerful  jaws.  It  is  found  under 
stones  and  in  clefts  of  rocks  at  low-water  mark,  or  more  commonly  in 
parchment-like  tubes  on  sheUy  beaches,  from  Cape  Cod  to  New  Jersey. 


Genus  Diopatra 

D.  cuprea.  This  is  one  of  the  largest  and  most  beautiful  annelidso 
It  is  found  from  Cape  Cod  to  South  Carolina  at  low-water  mark,  in  sandy 
mud-flats,  living  in  long  tubes  which  project  above  the  surface  two  or 
three  inches  and  are  hung  with  seaweeds  and  bits  of  foreign  matter. 
Diopatra  is  twelve  inches  or  more  in  length  and  one  half  of  an  inch  in 
breadth.  In  color  it  is  reddish-brown,  specked  with  gray,  and  has  a 
brilliant  whitish  or  opal-like  iridescence.  The  appendages  are  yellowish- 
brown,  specked  with  green.  The  body  is  flattened.  From  the  fifth  seg- 
ment long,  dull  to  bright  red,  much-branched  giUs,  resembling  plumes, 


WORMS 


179 


extend  nearly  to  the  end  of  the  worm.  On  the  ventral  side  of  the  para- 
podia  are  whitish  tubercles  with  a  dark  spot  in  the  middle.  These 
papillae  secrete  the  long,  broad  tube  in  which  the  worm  lives.  The  worm 
is  difficult  to  capture,  for  when  pursued  it  retreats  quickly  into  its  tube, 
which  is  so  large  that  it  can  easily  turn  around  within  it.    ( Plate  XL VIII.) 


Diopatra  cuprea.  Head  and  anterior  part  of  body,  showing  part  of  the  branchiae ; 

side  view. 


Genus  Arabella 

A,  opalina.  Body  cylindrical,  twelve  to  eighteen  inches  long,  one 
quarter  of  an  inch  wide  in  the  middle,  and  tapers  to  the  ends,  which  are 
comparatively  small ;  lateral  appendages  short ;  color  bronze,  with  bril- 
liant, opal-like  iridescence ;  head  small,  conical,  but  blunt  and  without 
tentacles ;  four  eyes  in  transverse  row  at  the  base  of  the  head  :  segments 
well  marked  ;  coils  into  spirals  when  outside  of  its  burrow.  Found  in 
compact  sandy  mud  at  low-water  mark  on  the  New  England  coast. 


Genus  Lumbriconereis 

L,  tenuis.  Twelve  inches  or  more  long,  and  slender,  like  a  fine  cord  j 
bright  red  and  somewhat  iridescent  -,  very  fragile.  Abundant  in  sandy 
mud  on  the  northern  New  England  coast,  and  found  from  New  Jersey 
northward. 

Family  GLYCEEiD.ffi 

These  worms  are  long  and  smooth,  with  numerous  segments. 
They  taper  at  both  ends.  The  head  is  smaU,  conical,  sharply 
pointed,  and  has  four  very  small  tentacles.      The  proboscis,  or 


180  MARINE  INVERTEBRATES 

pharynx,  when  protruded,  is  very  large  and  long,  and  appears  too 
large  for  the  worm.     The  proboscis  has   four  hook-like  jaws. 

These  worms  burrow  rapidly  and  disappear  almost 

instantly  into  the  mud  or  sand. 

Genus   Glycera 

G,  americana.  Color  red  or  purple ;  has  branched 
gills  on  upper  side  of  parapodia.  Found  from  South  Caro- 
lina to  Cape  Cod  on  sandy  and  muddy  shores  and  flats 
near  low-water  mark. 

G.  dibranchiata.  Has  a  simple  gill  on  both  sides  of  the 
parapodia ;  about  eight  inches  long  and  one  quarter  of  an 
inch  wide  in  the  middle ;  proboscis  one  inch  long  and  wider 
than  the  body  on  the  upper  end.  Abundant  from  New 
Jersey  to  Cape  Cod. 

ORDER  SEDENTARIA 

THE  TUBICOLOUS   WORMS 

Many  of  this  order  construct  tubes  in  which  they 
live  permanently.  Some  species  of  both  Sedentaria 
and  Errantia  have  habits  pertaining  to  the  other. 
These  worms  are  without  a  protrusible  pharynx  and 
without  jaws.  The  body  is  usually  divided  into  two 
or  three  sections  by  segments  and  appendages  of  dif- 
ferent forms.  They  have  hair-setse  on  a  limited 
number  of  segments  only,  varying  with  the  species ; 
the  remaining  segments  have  unmii,  or  hooked  comb- 
like rows  of  setae,  which  are  verjr  smaU,  but  often 
crowded  in  bunches.  Uncini  exist  also  on  segments 
having  hair-setae.  Parapodia  are  often  lacking  on 
the  posterior  parts  and  are  usually  without  cirri. 
The  gills  are  usually  confined  to  the  anterior  end  and 
are  sometimes  represented  by  tentacles  around  the 
head.  The  different  species  have  characteristic  tubes, 
formed  by  mucus  secreted  by  epidermal  glands. 
Sometimes  the  mucus  hardens,  making  a  parchment- 

Glycera  mec-  '  . 

/ceKi,with      like  tube:  again  it  cements  together  grains  of  sand, 

pharynx  ,.«■,,,  ,  /n  •  j. 

everted.       or  bits  of  shcU,  scawccds,  etc.     Some  species  secrete 


WORMS 


181 


calcareous  tubes ;  these  are  often  found  on  rocks,  in  coral,  and 
in  the  shells  of  mollusks.  The  anterior  end  of  the  body  is  more 
highly  developed  than  the  posterior  end. 


Fabiily  spionid^e 

Genus  Nerine 

N.  agilis.  Two  to  three  inches  long ;  slender ;  somewhat  flattened 
at  the  anterior  end ;  head  conical  and  sharp ;  the  two  tentacles  about 
one  half  of  an  inch  long ;  four  eyes  -,  color  reddish-brown,  light  green 
on  the  sides ;  gills  red ;  tentacles  greenish-white.  It  burrows  with  ex- 
treme rapidity  and  lives  on  exposed  beaches  near  low-water  mark. 

N.  coniocephala.  Two  and  a  half  inches  long,  one  sixteenth  of  an 
inch  in  diameter ;  head  conical ;  body  flattened  on  the  dorsal  side,  round 
on  the  ventral  side  j  has  two  long  tentacles  turned  backward  and  a  mem- 
brane on  the  gills  of  the  anterior  segments ;  gills  red  ;  bristles  long  and 
numerous. 

Family  cirratulid^ 

Worms  of  this  family  have  a  cylindrical  body,  more  or  less  atten- 
uated at  each  end ;  segments  similar  throughout  5  many  segments 
with  long,  filamentous 
cirri  which  act  as  gills ; 
and    a    conical    head. 
They  live  in  burrows. 

Genus  Cirratulus 

C,  grandis.  Four  to 
six  'inches  long  5  head 
acute ;  segments  numer- 
ous, short,  and  distinct  j 
color  dull  yellow,  or 
orange,  to  brown,  often 
iridescent  beneath;  ven- 
tral surface  somewhat 
flattened.  Numerous 

long,  filamentous,  red  to 
orange -colored  cirri  ex- 
tend nearly  the  whole 
length  of  the  body  and 
act  as  gills.  It  is  com- 
mon in  sand  and  gravel 
at  low-water  mark  from 
Cape  Cod  to  New  Jersey. 


Cirratulus  grandis. 


182 


MARINE  INVERTEBRATES 


Family  terebellidje 
The  body  is  cylindrical  and  largest  on  the  anterior  end;  there 
are  one  to  three  pairs  of  more  or  less  branched  gills  on  the  an- 
terior end,  and  the  ventral  surface  of  the  anterior  segments  is 

thickened  by  glands  which  secrete  mu- 
cus for  tube-building.  These  gland- 
spaces  are  called  shields. 

Genus  Thelepsus 

T,  cincinnatus.  Two  to  four  inches 
long ;  pale  red ;  marked  like  lace  work  on 
the  back ;  gills  have  numerous  nnbranehed 
filaments  arising  separately  in  two  trans- 
verse rows ;  tubes  thin,  transparent,  fl.exible, 
and  hung  with  foreign  substances  ',  attached 
along  the  whole  length. 

Genus  Amphitrite 

A.  ornata.  Twelve  to  fifteen  inches 
long;  flesh-color,  reddish,  or  brown;  three 
pairs  of  red  plume-like  gills  and  numerous 
flesh-colored  tentacles  around  the  anterior 
end;   tentacles   constantly  in  motion   and 

sometimes  extended  eight  or  ten  inches ;  tubes  a  quarter  of  an  inch  or 

more  in  diameter,  and  firm,  be- 
ing composed  of  sand  and  mud. 

It  is  found  under  stones  in  mud, 

gravel,  and  sand  at  low-water 

mark  from  Cape  Cod  to  New 

Jersey,   often    associated   with 

Cirratidus  grandis. 


Genera  I^oly cirrus, 
Chceto  branchus 

p.  eximius,  C.  sanguineus. 

These  are  two  species  of  bright- 
red,  fragile  worms,  found  under 
stones,  in  mud.  They  do  not 
form  tubes.  The  first  is  a  small 
worm,  the  second  twelve  to 
fifteen  inches  long.  Both  have 
long,  crowded  tentacles  extend- 
ing in  every  direction  and  dis- 
tended as  the  blood  flows  into 
them.      C.  sanguineus  has  ten- 


Amphitrite  ornata. 


Polycirrus  eximivs. 


WORMS 


183 


tacles  sixteen  inches  in  extent,  and  branched  gills  on 
short  pedicels  on  the  back.  They  are  common  in  mud 
at  low- water  mark  from  Cape  Cod  to  New  Jersey. 

Family  amphictenid^ 
Genus  Cistenides 

C,  Gouldii  constructs  conical  free  tubes  of  grains  of 
sand  in  a  single  layer ;  body  short  and  a  little  curved ; 
head  obliquely  flattened ;  two  broad  groups  of  golden 
bristles  turned  upward  on  each  side  of  the  anterior  end  5 
one  to  two  inches  long;  color  light  red  or  flesh- 
color,  mottled  with  red  or  blue.  This  is  a  common  worm, 
and  its  horn-shaped  tubes  are  so  plentiful  as  to  attract 
attention  on  sandy  shores.  They  will  repay  examination 
with  a  glass,  so  beautifully  are  they  built.  The  worm 
has  bunches  of  golden  bristles  arranged  in  two  rows 
close  to  the  flattened  anterior  end,  which  make  a  kind 
of  operculum  to  the  tube. 
This  feature  makes  the  spe- 
cies easy  to  identify.     The 

worm  is  transparent;   the  ^^    ftHMHi'vi    t 

internal    organs     showing  f^    ^^MMS    i 

through  give  it  the  various 
It  is  found  on  sandy  and 
muddy  shores  from  New  Jersey  northward. 

Family  maldanidje 

The  tubes  of  these  animals  are  formed 
of  sand,  a  short  portion  projecting,  and 
are  very  abundant  in  certain  places. 
There  is  a  horny  plate  on  the  upper 
surface  of  the  head,  and  the  skin  on  the 
sides  of  the  head  is  raised  in  folds. 
There  is  a  funnel-like  process  at  the 
posterior  extremity;  gills  are  lacking. 
Some  of  the  segments  in  the  middle  of 
the  body  are  longer  than  the  rest. 

Genus  Clymenella 

C,    torquata.      Body   long,   composed   of  Clymenella  torquata. 

twenty-two  segments;  the  fifth  segment  has  ^^  ^^^^  ^^^  ^^^^^^,^^  p^^^^^^.^_ 
a  collar-like  fold;  the  caudal  extremity  is  front  view;  &,  posterior  end;  c,  en- 
funnel-shaped  and  edged  with  papillse  ;  both    tire  animal,  side  view,  natural  size. 


Cistenides  Gouldii. 


bright   colors 


184  MARINE  INVERTEBRATES 

the  first  and  the  last  three  segments  are  bare,  the  rest  have  short  bristles 
above  and  hooks  below;  head  has  a  prominent  convex  plate  with  a 
raised  border ;  worm  pale  red,  with  bright-red  bands  around  the  seg- 
ments, sometimes  brownish.  It  constructs  nearly  straight  tubes  of  pure 
sand  close  to  low-water  mark  in  sheltered  coves,  and  ranges  from  New 
Jersey  northward. 

Genus  Maldane 

M,  elongata.  Six  to  eight  inches  long,  one  eighth  to  one  quarter 
of  an  inch  in  diameter ;  body  cylindrical,  cut  obliquely  at  both  ends ; 
head  bordered  by  a  sUght  fold ;  color  brown,  with  red  blood  showing 
through.  Found  in  sandy  mud  at  low-water  mark,  in  firm,  deep  tubes 
of  fine  mud,  on  the  New  England  coast. 

Family  arenicolid^ 

Genus  Arenicola 

A,  marina.  Five  to  ten  inches  long ;  brownish-green ;  body  cylin- 
drical, thickest  on  the  anterior  end  j  anterior  and  posterior  ends  without 
chsetse ;  twelve  to  thirteen  pairs  of  branched  red  gills  on  the  central  seg- 
ments. It  makes  burrows  eighteen  to  twenty-four  inches  deep  on  sandy 
southern  shores,  and  can  be  traced  by  castings  at  the  mouth  of  the  bur- 
row.    Commonly  known  as  "  lugworm,"  and  used  by  fishermen  for  bait. 

Family  sABELLiD.a: 

In  this  family  the  gills  arise  from  two  semicircular  bases  form- 
ing the  crown ;  the  second  lobe  of  the  anterior  extremity  is 
reversed  like  a  collar;  the  gill-filaments  have  secondary  pro- 
cesses, and  the  tubes  are  flexible,  composed  of  cemented  mud  or 
sand.  Found  under  stones,  the  tube  passing  around  the  stone 
and  opening  upward. 

Genus  Sabella 

S,  microphthalma.  Length  of  tube  one  and  a  quarter  inches, 
diameter  one  eighth  of  an  inch ;  body  olive-green,  specked  with  white ; 
wreath  of  tentacles  half  as  long  as  the  body ;  tentacles  pale  yellowish 
or  flesh-colored,  with  transverse  lines  of  darker  color.  It  is  found  on 
the  southern  New  England  coast. 

Family  serpulid^ 

This  family  forms  white  calcareous  tubes.  One  of  the  dorsal 
gill-fllaments  is  flattened,  forming  an  operculum,  or  cover,  with 


WORMS  185 

which  the  tube  is  closed  when  the  worm  has  withdrawn  itself 
inside.  The  tubes  are  commonly  found  attached  to  shells  and 
rocks,  usually  solitary,  but  sometimes  in  clusters,  crossing  and 
recrossing  each  other  on  the  surface  of  the  shell  or  rock.  Phime- 
like  gills  are  attached  to  the  anterior  end  of  the  body.  The  color 
differs  in  different  species.  These  worms  may  easily  be  mistaken 
for  the  moUusks  Vermetus,  which  live  in  similar  tubes  of  larger 
size,  growing  in  masses. 

Genus  Serpula 

S,  dianthus.  Tubes  often  three  inches  long  and  one  eighth  of  an 
inch  wide,  the  fixed  end  coiled  and  contorted,  free  end  with  circular 
opening  J  tubes  often  show  circular  ridges,  marking  periods  Of  growth ; 
operculum  funnel-shaped,  the  exterior  striated  and  the  edge  bordered 
with  short  processes;  wreath  of  gills  nearly  circular  and  divided  into 
two  symmetrical  parts ;  color  variable.  It  is  found  in  tide-pools,  also 
on  the  under  side  of  rocks  at  low-water  mark,  either  solitary  or  congre- 
gated in  masses,  and  ranges  from  Cape  Cod  to  New  Jersey. 

Genus  Spirorbis 

S.  borealis,  A  minute  calcareous  tube,  in  a  close,  flat  coil  attached 
on  one  side ;  easily  mistaken  for  a  minute  gasteropod  shell ',  worm  has 
an  operculum  and  wreath  of  gDls.  Found  on  the  fronds  of  seaweeds, 
on  sheUs,  etc. 

CLASS   GEPHYEEA 

This  class  of  animals,  once  placed  near  the  holothurians,  be- 
longs with  the  annelid  worms  on  account  of  their  mode  of  devel- 
opment, their  structure  being  entirely  dissimilar.  They  are 
without  segments  and  without  parapodia.  The  body-cavity  is 
filled  with  fluid  and  is  traversed  by  connective  tissue  and  fine 
muscular  fibers.  They  are  subcylindrical  animals  which  can 
retract  the  anterior  end  of  the  body.  The  mouth  is  surrounded 
by  tentacles,  or  by  tentacular  folds,  and  is  at  the  base  of  the 
proboscis.  They  live  in  fissures  of  rocks,  in  sand,  mud,  rock,  or 
coral,  and  in  deep  gasteropod  shells.     Their  distribution  is  general. 

ORDER  SIPUNCULOIDEA 
Genus  Sipiinculus 

S,  nudus.  The  body  is  cylindrical,  a  foot  or  more  in  length  when 
extended.    It  is  divided  into  two  portions.     The  anterior  end,  to  the 


186  MARINE   INVERTEBRATES 

extent  of  one  sixth  of  the  entire  length  of  the  worm,  is  capable  of  being 
withdrawn  into  the  remainder  of  the  body.  This  portion  is  called  the 
introvert.  The  introvert  is  retracted  by  means  of  special  muscles  form- 
ing a  sheath  around  the  gullet  and  connected  at  the  other  end  to  the 
body-wall  about  half-way  down  the  body.  It  is  narrower  than  the  rest 
of  the  body  and  is  covered  more  or  less  closely  with  small  horny  papillae 
which  turn  backward  and  overlap  like  scales.  The  rest  of  the  body  is 
divided  into  longitudinal  furrows  and  circular  markings,  giving  it  the  ap- 
pearance of  being  divided  into  squares.  These  markings  correspond  to 
muscles  which  lie  beneath.  The  introvert,  when  retracted,  leaves  at  the 
opening  a  lobed  and  plaited  fold  of  the  integument,  giving  the  appear- 
ance of  tentacles.  When  the  introvert  is  expanded  there  is  a  fringe-like 
funnel  around  the  mouth.  The  body  is  covered  with  a  horny  cuticle 
and  has  an  iridescent  luster.  The  animal  lives  buried  in  the  sand  and 
feeds  upon  sand,  deriving  its  nourishment  from  the  organisms  contained 
therein.  The  sipunculoids  pass  so  much  sand  and  mud  through  their 
bodies  that  they  are  said  to  modify  the  mineral  substances  on  the  bottom 
of  the  sea,  as  earthworms  do  the  soil  of  the  land. 

Genus  Phascolosoma 

J*.  Gouldii,  Body  cylindrical,  a  foot  or  more  in  length,  a  quarter  or 
half  of  an  inch  in  diameter  when  expanded;  but  the  body  constantly 
changes  in  size  and  shape  as  it  is  contracted  or  expanded ;  surface  of 
body  parchment-like  in  texture  and  marked  off  in  small  squares ;  color 
dull  white  to  light  brown.  It  is  found  on  the  New  England  coast  in 
sand  and  gravel  at  low-water  mark. 


IV 
MOLLUSCOIDA 


TABLE  SHOWING  THE  CLASSIFICATION  OF   THE  MOLLUSCOIDA 
DESCRIBED  IN   THIS  CHAPTER 

Class 
POLYZOA 


Subclass 
Ectoprocta 

(Excretory  opening  outside  lophophore;  mouth  in  center  of  circle 
of  tentacles;  tentacles  retractile) 


Order 
GYMNOLffiMATA 

(Circular  lophophore) 

Suborder 
CYCLOSTOMATA 

(Tubular  calcareous 
zocecia,  with  circu- 
lar apertures  devoid 
of  closing  appara- 
tus) 


Genera 


ARTICULATA 

(Erect  branches  divided- 
at  intervals  by  chitinous 
joints) 


Crista 


INARTICULATA      j  TubuUpova 
(Erect  or  adherent  zoa-^   DlCtStOpOVd 
rium ;  unjointed)  ^ 


Species 


C  eburnea 


T,  fiabellaris 
D.  patina 


Suborder 

CHEILOSTOMATA 

(Calcareous  or  chiti- 
nous zooecia,  usu- 
ally with  opercula; 
avicularia,  vibrac- 
ula,  and  ovicells 
often  present) 


CELLULARINA 

(Flexible  erect  forms) 


FLUSTRINA 

(Cells    quadrate;    front 
wall  of  zooecium  tnem- ' 


f^tea 
Eucratea 
Cellularia 
Caberea 

Bugula 


Flustra 


branous    or    depressed,  I  Membvauipora 

and  has  ridge-like  mar-  I 

^  ^  Escharella 

Mollia 


ESCHARINA 

(Zooeciuin   wholly  calci- 
fied) 


Cellepora 


^,  anguinea 
E,  chelata 
C.  ternata 
C.  Ellisii 

{B,  turrita 
B,  Miirrayana 
B,  flabellata 

F,  mefnbranacea 
( M.  pilosa 
I  M,  lineata 
\  M.  temiis 

E.  variabilis 

M.  hyalina 
r  C.  scabra 
}  C,  ramulosa 
i  C,  pufnicosa 


188 


MOLLUSGOIDA 


189 


Suborder 

CTENOSTOMATA 

(Horny  or  gelatinous  zooecia,  having 
tooth-like  processes  which  close  the 
apertures  xvhen  the  tentacles  are 
retracted) 


Grenera 
Alcyonidium 

Vesicularia 


Species 

'A,  ramosum 

A,  hirsutum 

A,  hispiduni 

.A,  parasiticum 

V.  dichotoma 

V,  ciistata 


Subclass 
Entoprocta 

(Excretory  opening  xoithin  lophophore ;  mouth  near  margin  of  area,  tvhich  is  surrounded  by 
tentacles ;  tentacles  roll  up  instead  of  being  retracted) 


JPedicellina 


P,  americana 


TERMS  USED  IN  DESCRIBING  POLYZOA 

Avicula'ria:  Specifically  modified  zooecia,  resembling  a  bird's 
headj  found  only  in  the  CJieilostomata. 

Brmvn  bodies :  Brown  pigment-masses  contained  in  tbe  zo- 
oecia  and  derived  from  the  breaking  down  of  the  polypides. 

Lo'phophore :  The  disk  bearing  the  mouth  and  circlet  of  ciliated 
tentacles. 

Orifice :  The  open  end  of  the  zooecium. 

Ovicell :  The  receptacle  in  which  the  eggs  develop. 

JPe'ristome :  The  ridge  around  the  orifice  of  cell. 

Po'lypide:  The  parts  of  the  animal  within  the  zooecium. 

Vihra'cula :  A  lashing  filament,  or  specifically  modified  zooecia, 
found  only  in  the  Cheilostomata. 

Zoa'rium :  The  whole  colony. 

Zow'cium:  The  body- wall  of  a  single  individual. 


190 


POLYZOA 

AMONG  the  numerous  objects  to  be  found  on  the  beach  at 
XjL  low  tide  are  the  Folyzoa,  of  which  there  are  said  to  be  seven- 
teen hundred  named  species  of  the  marine  forms.  These  little 
animals,  although  so  plentiful,  are  Inconspicuous,  and  it  may  be 
said  that  their  very  existence  is  not  known  to  those  who  are  not 
professed  naturalists ;  yet  they  are  easy  to  see,  incrusting  with  a 
delicate  calcareous  lacework  the  surface  of  stones  and  shells  and 
seaweeds  in  the  tide-pools,  and  hanging  from  the  rocks  like 
branches  of  delicate  seaweeds.  There  is  hardly  a  frond  of  even 
the  fine  red  algae  on  which  cannot  be  found  the  little  tube  holding 
shelly  saucers,  or  the  creeping  stems  or  branches  of  polyzoans. 
Any  one  of  these  little  masses,  when  examined  with  a  pocket- 
glass,  will  surprise  one  with  its  delicate  and  beautiful  structure. 

This  class  of  animals  is  also  called  Bryosoa,  and  certain  species 
have  the  common  names  of  sea-mats  and  corallines.  They  are 
broadly  divided  into  two  groups,  namely,  the  erect  and  the  in- 
crusting  forms.  Those  having  tree-  or  plant-like  shapes  resemble 
seaweeds,  while  the  colonies  which  spread  over  stones,  shells,  and 
algae  resemble  moss,  hence  the  name  Bryosoa  (moss-animals). 
Both  groups  have  the  general  appearance  of  hydroids,  because, 
like  them,  they  are  colonies  having  plant  forms  and  having 
their  organisms  inclosed  in  cup-like  sheaths.  The  resemblance, 
however,  is  but  a  superficial  one,  for  the  Folyzoa  have  a  much 
higher  organization,  each  animal  of  the  colony  being  a  separate 
and  distinct  individual.  They  can  easily  be  distinguished  by  the 
hair-like  processes  on  the  tentacles.  The  ciliated  tentacles  and 
complete  alimentary  system  are  the  conspicuous  differences  be- 
tween these  colonies  and  those  of  the  hydroids. 

The  Folyzoa  are  very  numerous  and  form  a  most  attractive 

191 


192  MARINE  INVERTEBRATES 

group.  They  are  plentiful  everywhere,  occurring  between  tide- 
marks  and  at  great  depths  on  the  floor  of  the  sea.  Rocks  pro- 
tected from  the  sun  are  often  incrusted  with  the  calcareous  forms, 
while  branching  species  hang  from  the  rocks  and  adorn  rock 
pools.  Memhranipora,  in  lace-like  sheets,  will  be  found  on  the 
larger  seaweeds  as  well  as  on  various  submerged  objects.  The 
beautiful  little  Crista  may  be  looked  for  on  the  fronds  of  red 
algaB,  and  Alcyonidium,  in  soft  moss-like  patches,  on  Fucus.  On 
some  beaches  are  scattered  the  sea-mats,  Flustra  foliacea,  looking 
like  bits  of  brown  paper.  A  pocket-lens  will  reveal  the  marvel- 
ous and  orderly  arrangement  of  the  two  layers  of  cells,  or  zooecia, 
placed  back  to  back.  There  ^s  not  a  more  surprising  object  in 
the  animal  kingdom  than  a  living  branch  of  Biigula.  The  cells 
on  its  spiral,  profusely  branched  clusters  have  appendages  re- 
sembling a  bird's  head,  with  its  bill  constantly  opening  and  shut- 
ting. Of  the  erect  polyzoans  some  are  entirely  calcareous  and 
rigid;  such  species  live  in  deep  water,  and  their  colonies  are 
called  corallines,  as  are  also  the  calcareous  algae.  They  have  ex- 
isted in  vast  numbers  since  early  geologic  times,  and  are  plentiful 
in  the  Tertiary  deposits,  known  as  Coralline  Crags.  Other  erect 
forms  have  a  calcareous  framework,  which  is  not  continuous,  but 
has  horny  intervals,  so  that  the  colonies  are  flexible  and  can  be 
swayed  by  the  tides  in  shallow  water  where  they  live.  Others 
have  complete  horny  exoskeletons.  The  same  differences  occur 
in  the  incrusting  forms,  those  on  the  seaweeds  being  either  flex- 
ible, so  that  they  bend  with  the  plant,  or  if  entirely  calcareous 
are  so  small  that  they  do  not  break  when  the  plant  sways  to  and 
fro.  Still  others  are  gelatinous  and  resemble  bits  of  sponge. 
The  calcareous  forms  are  usually  ornamented  with  ridges  which 
form  beautiful  patterns. 

The  individuals  of  the  polyzoan  colonies  are  small  polyp-like 
organisms  which  have  a  cup-like  inclosure  of  horny  or  of  calca- 
reous substance,  or  of  the  two  combined,  as  mentioned  above. 
This  inclosing  sheath  is  the  exterior  or  cuticle  of  the  animal  and 
is  called  the  zooecium,  the  whole  colony  being  called  the  zoariimi. 
The  animal  substance  within  the  zooecium  is  the  pohjpide,  and 
consists  of  the  mouth,  tentacles,  and  alimentary  system.  A  disk 
at  the  anterior  end  of  the  body,  bearing  the  circle  of  tentacles,  is 


POLYZOA  193 

the  lopJiophore  ;  it  is  a  contractile  body,  being,  with  the  tentacles, 
protruded  from  the  zooecium  or  drawn  within  it  at  will.  In 
some  species  the  orifices  of  the  zocecia  are  surrounded  with  spines ; 
others  have  lids,  called  opercula,  which  shut  down  when  the  poly- 
pides  are  retracted.  A  singular  modification  of  the  zocecia  is 
seen  in  the  genus  Biigula,  where  peculiar  shapes  like  birds'  heads, 
called  avmdaria,  occur.  In  these  singular  appendages  the  upper 
beak  is  hooked,  while  the  lower  one,  or  mandible,  is  the  operculum 
of  the  zooecium.  These  constantly  open  and  shut  by  means  of 
muscles,  and  although  their  function  is  not  certainly  known,  it  is 
thought  that  they  capture  prey.  Other  modifications  are  whip- 
like processes,  or  flagellate  filaments,  called  vihracula,  which  con- 
stantly beat  the  water.  In  many  of  the  zocecia  of  the  colony 
there  are  dark-colored  masses,  called  hroivn  bodies.  These  are 
formed  by  the  degeneration  of  the  polypides,  which  at  certain 
periods  break  down,  their  tentacles  and  alimentary  system 
ceasing  to  act  and  becoming  brown  masses.  The  body- wall  then 
puts  out  a  bud  internally  and  forms  a  new  polypide,  which  ab- 
sorbs, or  passes  out,  the  brown  body.  The  term  of  life  of  a  sin- 
gle polypide  is  not  known,  but  in  every  colony  many  such  trans- 
formations are  constantly  taking  place. 

The  colonies  originally  start  from  larvae  produced  in  the  ovi- 
cells  of  the  zoaria.  The  ovicells  are  sometimes  very  large  and 
pear-shaped,  occurring  at  intervals  on  the  stems ;  or  there  may 
be  one  at  the  top  of  each  zooecium.  They  look  like  pearls.  A 
larva,  when  liberated,  swims  about  for  a  time,  then  attaches  itself 
to  a  fixed  object,  and  increases,  by  budding,  into  some  one  of  the 
various  forms  which  the  colonies  take. 

SUBCLASS  ECTOPROCTA 

ORDER    GYMNOLiEMATA 
Suborder  cyclostomata 

erect  or  creeping  polyzoa 

The  zooecia  are  more  or  less  cylindrical ;  the  upper  ends  are 
sometimes  completely  free  and  sometimes  closely  adherent.     The 

13 


194 


MARINE  INVERTEBRATES 


opening  of  the  cell  has  no  opercnlum„     Ovicells,  containing  the 
embryos,  appear  like  pear-shaped  swellingSo 


Genus  Crista 

C*  eburnea.  This  species  is  found  in  tide-pools  on  algae,  especially 
on  the  red  seaweeds,  growing  in  bushy  tufts  from  one  half  of  an  inch  to 
an  inch  high.  Calcareous,  with  horny  joints;  cells  in 
two  rows,  semi-alternate,  cylindrical,  free  at  one  end, 
bent ;  no  operculum  5  ivory-white ;  ovicells  large  and 
pear-shaped.  Common  from  Long  Island  Sound  north- 
ward and  on  the  Pacific  coast. 


Genus  Tuhulipora 


T,  fiabellaris.      This 
slender  branched  algse, 


species  is  found 
in  coral-like 


masses 


attached  to 
of  long, 


crooked,  tubular  cells  united  at  the  base  and  spreading 
into  fan-shapes  placed  flat  against  the  fronds.  It  is 
sometimes  one  quarter  of  an  inch  in  diameter.  On  the 
same  alga  may  often  be  found  Crisia^  Mollia,  and  Celle- 
pora.     (Plate  XLIX.) 

Genus  Diastopora 


J),  patinao  Tubular  cells  rise  from  a  saucer-shaped 
disk  about  a  quarter  of  an  inch  in  diameter ;  cells  lie 
obliquely  or  stand  erect,  and  are  crowded  toward  the 
center;   margin   of   disk  without  cells;   colony  white 

and  calcareous.      Found  on  algse   and    eel-grass   from   Long   Island 

Sound  northward. 


Crisia  eburnea ;  a 
Tbranch  bearing  ovi- 
cells, highly  magni. 
fied. 


Suborder  cheilostomata 

In  this  suborder  the  zooecia  are  either  horny  or  calcareous,  and 
the  orifices  are  usually  surrounded  with  spines  and  have  opercula. 
The  orifices  generally  have  raised  margins,  or  peristomes.  Ovicells 
form  helmet-like  coverings  overhanging  the  orifices. 


Genus  JEtea 

M,  anguinea.  Delicate,  white,  creeping,  calcareous  stems,  from  which 
rise  numerous  club-shaped  cells,  about  one  eighth  of  an  inch  high,  each 
one  with  an  aperture  in  the  end.  This  species  creeps  in  wavy  lines 
along  the  fronds  of  algse,  and  is  frequently  found  on  Basya,  Griffithsia, 
Plocamium,  and  eel-grass. 


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POLYZOA 


195 


Genus  JEucratea 

E.  chelata,  A  small,  delicate  species  rising  from  a  creeping  stem. 
It  has  branches  composed  of  single  rows  of  horn-shaped  cells  having  an 
oblique  aperture  on  the  side.  Found  at  extreme  low-water  mark  on 
hydroids,  shells,  stones,  and  Fucus.     (Plate  XLIX.) 

Genus  Cellularia 

C.  ternata,  Zoarium  filamentous,  spreading,  about  one  inch  high, 
white,  calcareous,  branched  in  a  forking  manner  5  cells  long,  narrowest 
at  base,  arranged  in  series  of  three  and  on  the  same  plane,  apertures 
oblique  and  facing  one  way ;  horny  joint  between  each  cluster  of  cells. 
This  species  grows  in  deep  water  from  Cape  Cod  northward,  and  is  found 
on  objects  washed  upon  the  beach.     (Plate  XLIX.) 

Genus  Caberea 

C,  Ellisii,  Zoarium  erect,  with  fibrous  base,  leaf -like,  branches  in  a 
forking  manner ',  branches  straight,  stiff,  narrow,  spreading  5  cells  ar- 
ranged in  rows  of  three,  adherent  throughout  j  long  bristles  emanate 
from  near  base  of  many  cells ;  egg-capsules  globular,  smooth,  pearly. 
Common  from  Cape  Cod  northward  in  deep  water.      (Plate  L. ) 

Genus  JBugula 

B.  turrita.  This  is  a  very  abundant  species,  found  everywhere  along 
the  coast  from  Maine  to  North  Carolina.     Large  quantities  of  it  are 


1,  Bugula  turrita,  enlarged  ;  2,  the  same,  a  branchlet,  highly  magnified; 
3,  the  same,  a  branchlet,  bearing  ovicells. 


196 


MARINE  INVERTEBRATES 


sometimes  thrown  npon  the  beach  by  storms.  It  grows  in  erect  tufts, 
sometimes  a  foot  long,  and  is  much  branched  j  the  branches  grow 
around  the  stem  in  a  spiral  manner,  forming  dense  clusters.  The  lower 
part  of  the  stem  is  often  naked  (having  lost  the  branches)  and  bright 
orange  in  color,  while  the  tufts  of  branches  at  the  top  are  pearly- white 
or  yellowish.  The  cells  are  long,  with  a  long,  pointed  spine  on  the  upper 
outer  angle.  Like  all  species  of  Bugula,  it  has  bird-head  appendages, 
which  can  be  seen  under  a  powerful  glass.    (Plate  L.) 

B,  Murrayana,  Clusters  of  broad,  thin,  flexible  fronds,  one  to  two 
inches  high,  attached  by  a  slender  base  and  spreading  in  entangled 
masses  5  fronds  wedge-shaped,  flat,  dividing  in  a  forking  manner ;  outer 
cells  have  bristle-like  filaments,  which  constantly  beat  the  water;  all 
cells  have  avicularia,  or  bird-head  appendages.     (Plate  L.) 

B.  fldbellata.  Fan-shaped  fronds  of  flat  branches,  divided  in  a  fork- 
ing manner ;  the  cells  are  arranged  in  four  or  five  longitudinal  rows, 
are  oblong,  with  a  spine  at  each  side  of  the  circular  aperture,  and 
are  capped  with  pearl-like  ovicells.  This  species,  like  others  of  the 
genus,  bears  the  very  singular  structures  known  as  avicularia,  or  bird- 
head  appendages.  They  show,  under  a  strong  glass,  a  hooked  beak,' 
like  that  of  the  hawk  or  parrot.  These  beaks  are  attached  by  flexible 
stems  and  are  provided  internally  with  powerful  muscles  by  which  they 
are  constantly  opened  and  closed ;  the  beak  can  bite  with  considerable 
force.   In  this  species  they  are  attached  to  the  sides  of  the  cells.   (Plate  L.) 

G-ENus  Flustra 

F.  membranacea.  This  species  forms  gauze-like  incrustations  on  the 
fronds  of  seaweeds,  and  is  common  on  Fucus  and  Laminaria,  spreading 
irregularly  over  several  inches  of  space.  The  cells  are  oblong,  quad- 
rangular, with  a  blunt,  hollow  spine  at  each  angle.  Many  species  have 
simple  horny  tubes,  closed  on  top,  rising  from  some  of  the  cells  to  the 
height  of  half  an  inch.     (Plate  LI.) 


Genus  Me^nhranipora 

M,  pilosa.    An  incrusting  variety,  composed  of  a  single  layer  of  cells 
spreading  irregularly  over  the  surfaces  of  stones,  shells,  and  seaweeds, 

sometimes   completely  covering  the 
fronds   of    Chond7'us  crispus,  Phyllo- 
pora,   Rhodymenia,   and  other  algae. 
The  cells  are  membranaceous,  with  a 
calcareous  rim,  and  have  one  long 
hair  and  several  small  ones  surround- 
ing the  large  roundish  apertures.     It  is 
found  in  abundance  on  the  shores  from 
Long  Island  Sound  to  the  Arctic  Ocean. 
M.  lineata.     Cells  oblong,   crowded, 
closely  adherent ;  slender  spines  on  edge 
of  aperture,  which  bend  over  and  meet 
se.*:ratT»aS"L°iT;««t    across  it :  incrusts  jocks  and  sheUs  m 

porapiiosa;  a  Single  cell,  seen  in  profile.      broad,     thm,     radiatmg      patcbCS  ^      CellS 


PLATE   LI. 


Flustra  f oliacea.  1,  Flustra  membranacea ;  2,  3,  F.  mem- 

1,  2,  Cellepora  pumicosa,  natural  size ;     branacea,  magnified. 
3,  C.  pumicosa,  magnified ;  4,  C.  ramulosa.  Vesicularia  dichotoma. 


POLYZOA  197 

much  smaller  and  naiTower  than  those  of  M.  pilosa  ;  easily  distinguished 
from  that  species  by  its  manner  of  spreading  and  the  absence  of  the  one 
long  hair.     Common  from  New  Jersey  northward. 

M,  tenuis.  Common  on  pebbles,  often  covering  theii-  whole  surface 
with  a  lace-like  incrustation  of  very  small  oblong  cells  having  a  three- 
lobed  aperture.    Found  in  Long  Island  Sound  and  north  to  Cape  Cod. 

Genus  JEscharella 

E.  variabilis.  This  species  forms  calcareous  incrustations  on  shells 
or  pebbles.  The  layers  are  thin,  but  eventually  overlap  one  another,  and 
the  incrustation  sometimes  becomes  an  inch  thick  and  resembles  coral. 
The  color  of  the  living  animal  is  dull  red.  The  species  ranges  from  Cape 
Cod  to  South  Carohna,  and  is  abundant  in  Long  Island  Sound. 

Genus  Mollia^ 

M,  hyaliua.  Cells  subcylindrical,  irregular,  transparent,  smooth, 
and  more  or  less  obhque.  The  species  forms  small  circular  disks  on  algse 
in  tide-pools. 

Genus  Cellepora 

C,  scabra.  It  forms  branching,  coral-like  masses  on  slender  red 
algae. 

C,  ra^nulosa.  Branches  cylindrical,  rough,  dividing  in  a  forking 
manner,  spreading,  two  to  three  inches  high,  calcareous;  cells  urn- 
shaped,  irregularly  arranged,  apertures  contracted,  long  spine  on  the 
outer  edge.  It  is  found  in  deep  water  attached  to  shells,  and  in  tide- 
pools,  where  it  grows  chiefly  on  Sertularia  and  other  hydroids  and  on 
slender  red  algae.  It  ranges  from  Long  Island  Sound  to  Greenland. 
(Plate  LL) 

C,  putnicosa.  Cells  urn-shaped,  irregularly  crowded  together,  form- 
ing a  conglomeration  of  porous,  brittle  masses,  not  exceeding  an  inch  in 
breadth,  usually  round  when  smaU,  oblong  and  knobbed  when  large ; 
spine  on  outer  margin  of  aperture.  It  incrusts  stones  and  the  stems  of 
Fucus.     (Plate  LL) 

Suborder  ctenostomata 
Genus  Alcyontdiiim 

A.  ramosuni.  Twelve  to  fifteen  inches  high;  much  branched; 
branches  smooth,  cylindrical,  one  third  of  an  inch  in  diameter,  usually 
crooked ;  branches  in  a  forking  manner ;  color  rusty-brown.  Abundant 
in  shallow  water,  attached  to  rocks,  from  New  Jersey  to  Cape  Cod. 

A,  hirsutum,  A  species  common  on  seaweeds,  sometimes  completely 
covering  them,  forming  dirty,  straw-colored,  thick,  cartilaginous  crusts 
covered  with  numerous  conical  papillae.  These  are  the  cells,  or  zooecia; 
they  are  surrounded  with  spines.  Circular  yellow  spots  occur  over  the 
surface,  which  are  clusters  of  eggs.  A  good  pocket-lens  will  show  the 
cells,  laid  m  beautiful  order,  and  perhaps  the  extended  tentacles.  Found 
from  Long  Island  Sound  northward. 


198  MARINE  INVERTEBRATES 

A»  hispidiun.  One  of  the  most  common  species  found  incrusting 
the  fronds  of  Ascophyllum  at  low- water  mark.  It  forms  fleshy,  brown, 
soft  crusts  of  moderate  thickness,  and  has  spines  scattered  over  the 
otherwise  smooth  and  glistening  surface.  The  cells  are  inconspicuous, 
and  each  one  has  five  long  rigid  bristles.  Habitat,  Long  Island  Sound 
to  Greenland. 

A,  j^ct^r'dfiiticum.  It  forms  thin,  earthy  crusts  on  algae  and  hydroids. 
The  surface  is  porous  j  the  cells  are  distant  and  arranged  irregularly, 
and  seem  as  if  composed  of  sand  cemented  with  mud. 

Genus  Vesicularia 

V,  dichotoma  {Valkeria pustulosa).  This  species  grows  in  clus- 
ters of  crowded  slender  stems,  which  branch  in  a  forking  manner,  the 
branches  dividing  in  different  planes,  making  a  tree -like  form  one  to 
three  inches  high.  At  the  iDoints  where  the  branches  divide  is  a  dark, 
opaque  substance,  and  at  these  points  also  the  cells  are  crowded  in  clus- 
ters of  spiral  rows  and  are  greenish-brown  in  color.  The  dark  spots 
are  in  marked  contrast  to  the  white  translucent  substance  of  the  rest 
of  the  stem,  giving  a  spotted  aspect  to  the  whole.    (Plate  LI.) 

F.  custata.  Delicate,  thread-like,  jointed  stems,  with  slender  oppo- 
site branches;  cells  small  and  elliptical,  arranged  mostly  in  clusters. 
Found  creeping  like  a  small  dodder-plant  over  other  polyzoans,  hy- 
droids, and  seaweeds. 

SUBCLASS   ENTOPROCTA 

Genus  Pedicellina 

P,  americana,  A  very  small  species.  Club-like  zooecia  rise  from 
slender,  white,  creeping  stems ;  tentacles  roll  up  instead  of  retracting 
into  the  cups.     Found  on  hydroids,  other  polyzoans,  and  algse. 


V 

ECHINODEEMATA 


Phylum 
EGHINODERMATA 

Classes 
ASTEROIDEA 

(  Starfishes) 

OPHIUROIDEA 

(Brittle-stars) 

ECHINOIDEA 

(Sea-urchins) 

HOLOTHUROIDEA 

(Sea-cucumbers) 

CRINOIDEA 

(Feather-stars  and  Sea-lilies) 


200 


TERMS   USED  IN  DESCRIBING  THE  STRUCTURE  OF  ECHINODERMS 

Aho'ral  surface:  The  side  opposite  the  mouth. 

Ambula'cra :  Tubular  feet  used  in  moving. 

Ambulacral  zones :  The  five   areas    containing  the   rows    of 
tube-feet. 

Ampul'lce:  Reservoirs  or  vesicles  at  the  base  of  the  tube-feet. 

Auricula'ta:  The  larval  stage  of  holothurians. 
.  Bipinna'ria  or  Branchiolaria :  The  larval  stage  of  starfishes. 

Dorsal  surface:   The  back  of  the  animal,  generally,  but  not. 
necessarily,  the  upper  side. 

Exoskeleton :  Outside  framework  or  support,  differing  from  a 
true  skeleton  which  lies  inside  the  body. 

Interambulacral  areas :   The  five  areas  between  the  ambula- 
cral zones. 

Larva:  The  animal  in  a  stage  of  development  from  the  time 
it  leaves  the  Qg^  until  it  reaches  the  complete  form  of  the  species. 

Madreporic  plate :  A  sieve-like  plate  of  carbonate  of  lime. 

Oral  surface :  The  side  on  which  the  mouth  is  placed. 

Ossicles :  Calcareous  plates  which  cover  the  body  and  form  the 
exoskeleton. 

Pedicella'rice :  Small  spines  which  have  divided  ends,  like  scis- 
sors or  forceps. 

Flu'teus:  The  larval  stage  of  sea-urchins. 

Po'lian  vessels :  One  to  ten  sacs  arising  from  the  ring-canal. 

Bing-canal :     The  canal  around  the  mouth. 

Spines :  Processes  which  rise  from  the  surface  of  the  animal. 

Stone-canal :  A  calcareous  tube  leading  from  the  madreporic 
plate  to  the  ring-canal. 

Suckers :  Sucking-disks  on  the  ends  of  the  tube-feet. 

Ventral  surface:  The  side  opposite  the  dorsal  surface. 

Water-vascular  system:  A  series   of  canals  which   conduct 

water  through  the  animal. 

201 


ECHINODEEMATA 

THE  echinodermSj  altlioiigli  their  shapes  are  very  unlike  in 
the  different  classes,  have  the  same  general  internal  struc- 
ture, and  also  other  features  which  place  them  together  in  one 
group.  They  are  radiates  (page  113)  of  the  highest  typej  they 
have  an  exoskeleton  ]  and  many  of  them  are  beset  with  spines, 
from  which  the  name  is  given.  They  have  locomotor  organs,  the 
amhulacra,  and  a  tvater-vascular  system  peculiar  to  themselves. 
Some  have  the  very  strange  power  of  casting  off,  and  developing 
again,  parts  of  the  body. 

The  development  from  the  egg  to  the  adult  is  remarkable,  and 
of  unusual  interest  to  naturalists.  The  larval  stage  of  echino- 
derms  is  so  unlike  the  mature  animal  that  for  a  long  time  the 
larvse  were  thought  to  be  another  class  of  animals,  and  therefore 
were  given  the  names  which  they  still  retain. 

In  observing  echinoderms  it  will  be  seen  that  the  dorsal  part 
is  carried  uppermost  by  some,  such  as  the  starfishes  and  sea- 
urchins.  In  the  former  the  back  is  broad  and  extended;  in  the 
latter  it  is  curved  and  contracted.  But  in  crinoids  the  back  is 
carried  downward  and  is  extended  like  a  stalk ;  in  the  sea-cucum- 
bers (holothurians)  the  dorsal  and  ventral  surfaces  are  parallel 
with  the  long  axis  of  the  cylindrical  body,  instead  of  being  on  a 
plane  with  the  mouth  and  excretory  opening.  Owing  to  the 
unusual  positions  of  the  dorsal  and  ventral  surfaces,  the  terms  oral 
(mouth  side)  and  aboral  (side  opposite  the  mouth)  are  generally 
used  in  describing  these  species. 

The  surface  of  the  body  is  divided  definitely  by  the  ambulacra, 
the  cwibulacral  zones,  and  the  interam'bidacral  spaces,  but  differ- 
ently in  the  different  classes.     The  movement  of  the  animals  is 

202 


ECHINODERMATA 


203 


effected  by  means  of  the  tube-feet,  or  ambulacra.  These  have 
suckers,  which  are  attached  or  released  by  the  power  of  the  water- 
vascular  system.  The  madreporic  plate,  which  can  be  distinctly 
seen  in  starfishes  at  the  angle  of  two  of  the  arms,  is  a  calcareous 
porous  plate  which  opens  into  the  stone-canal.  This  canal  passes 
through  the  body  and  opens  into  a  circular  tube  which  runs 
around  the  mouth.  A  system  of  canals  extends  from  this  circum- 
oral  tube,  or  ring-canal,  and  eventually  one  canal  opens  into 
each  tube-foot.  Water,  entering  by  the  madreporic  plate,  passes 
through  the  various  canals  and  into  the  tube- feet,  which  it  dis- 
tends. When  the  feet  are  pressed  against  a  substance  and  the 
water  is  withdrawn,  a  vacuum  is  formed,  which  causes  the  disk- 
ends  of  the  feet  to  act  like  suckers.  When  the  feet  are  again 
flooded  the  hold  is  relaxed.  Thus  the  animal  drags  its  body 
along  with  a  slow,  gliding  motion.  The  madreporic  plate,  being 
calcareous,  is  said  to  act  as  a  filter^  purifying  the  water  as  it 
passes  into  the  body,  which  it  furnishes  with  oxygen  as  well  as 
with  locomotive  power. 

A  curious  organ  found  in  the  Uchinoidea  (sea-urchins)  is  called 
Aristotle^s  lantern.  It  is  a  complicated  arrangement,  not  fully 
understood,  having  forty  parts,  and  is  connected  with  the  alimen- 
tary system.  One  of  the  parts  is  the  mouth, 
over  which  five  teeth  project.  These  teeth 
grasp  and  grind  the  food.  The  exoskeleton 
is  composed  of  plates  of  carbonate  of  lime, 
called  ossicles,  which  cover  the  surface  of  the 
body.  The  ossicles  are  of  various  sizes  and 
shapes,  and  are  one  of  the  determining  fea- 
tures in  classification.  They  may  be  scattered 
spicules  of  lime,  separated  plates  joined  by 
connecting  rods,  or  overlapping  plates;  or 
they  may  be  fitted  together  so  as  to  form  a 
continuous  shell.  The  starfishes  are  usually 
carnivorous,  the  sea-urchins  usually  vegetarian,  while  the  holo- 
thurians,  after  the  manner  of  worms,  take  in  sand  and  mud,  deriv- 
ing their  nourishment  from  the  organic  particles  contained  in 
them.     All  echinoderms  live  in  the  sea. 


Aristotle's  lantern. 


TABLE    SHOWING   THE   CLASSIFICATION  OF   THE   STARFISHES 
DESCRIBED  IN  THIS  CHAPTER. 


Class 
ASTEEOIDEA 

(Starfishes) 

Order  PHANEROZONIA 

C  Ossicles  not  crowded ;  large  marginal  ossicles ;  spines  only  on  dorsal  surface  ; 

pedicellarice  sessile) 

Species 

O.  corniculatus 
A.  articularis 
JP.  florce 
i  JL,  senegalensis 
\  L,  clathrata 
(  L,  alternata 
M,  cequalis 
H,  phrygiana 
\  P.  occidentalis 
\  I*,  reticularis 

JV.  armata 
J  A.  folium 
(  A.  miniata 


Families 

Genera 

FORCELLANASTERID^ 

Ctenodiscus 

(Astropecten 

1  I*silaster 

ASTROPECTINIDJE 

< 

lAiidia 

PENTAGONASTERIDiE 

\ 
Mediaster 

ANTHENEIDJE 

Hippasteria 

PENTACEROTID^ 

^  JPentaceros 
(  Nidorella 

ASTERINIDiE 

\  Asterina 

Order  CRYPTOZONIA 

(Ossicles  croivded;  pedicellarice  stalked) 

S  Solaster 


SOLASTERIDJE 

ECHINASTERIDiE 
HELIASTERIDJE 

ASTERIIDJE 


Crossaster 
Cribrella 
Echinaster 
Heliaster 

204 


S,  endeca 

S.  decemradiata 

C.  papposus 

C.  sanguinolenta 

E,  sentus 

H,  multiradiata 

A,  vulgaris 

A,  Forbesii 

A,  ochracea 

'A,  gigantea 


CLASS  ASTEROIDEA 

THE  STARFISHES 

THESE  animals  are  named  from  their  star-shaped  outline. 
Some  have  five  long,  spreading  arms  diverging  from  a 
small  disk,  which  is  hardly  more  than  their  point  of  union ;  others 
have  a  large  body  with  short  arms,  which  are  like  angular  projec- 
tions of  the  body,  giving  a  pentagonal  shape.  Some  genera  have 
a  greater  number  of  arms  than  others ;  Solaster  has  eleven  to 
thirteen,  and  Eeliasier  (the  sun-stars,  found  on  the  west  tropical 
coast)  has  thirty  to  forty. 

The  mouth  of  the  starfish  is  in  the  center  of  the  ventral  side. 
A  ventral  or  ambulacral  groove  extends  through  each  arm.  In 
these  grooves  the  ambulacra,  or  tube-feet,  are  arranged  in  rows. 
The  ambulacra  are  hollow,  cylindrical  bodies,  each  of  which  has  a 
sucker  at  one  end,  and  is  connected  at  the  other  end  with  a  little 
globular  body,  the  ampulla.  The  ventral  groove  forms  a  ridge  in 
the  body-cavity.  It  is  called  the  ambulacral  zone,  and  is  formed 
by  a  double  row  of  elongated  plates,  which  meet  and  form  a 
raised  line  along  the  middle  of  the  inside  of  the  arms,  and  appear 
like  ribs ;  between  them  lie  the  ampullae.  These  plates  are  called 
the  ambulacral  ossicles.  Numerous  other  ossicles  extend  over  the 
surface,  buried  in  the  integument  of  the  body,  making  a  calcare- 
ous network,  or  exoslceletoji.  The  ossicles  are  connected  by  muscles 
so  that  the  animal  is  not  rigid,  but  is  able  to  bend  the  body  and 
even  creep  through  comparatively  small  places.  The  ossicles  are 
covered  with  spines  of  two  kinds.  The  very  minute  ones  are  the 
pedicellaricB,  and  have  a  jointed  end  which  opens  and  shuts  like  a 
pincers.  Their  principal  use  seems  to  be  to  remove  waste  matter 
or  other  substances  from  the  body,  keeping  it  free  and  clean.  The 
pediceUarite  are  arranged,  in  some  species,  in  circles  around  the 

205 


206 


MARINE   INVERTEBRATES 


bases  of  the  spines,  and  form  groups  over  the  dorsal  surface. 
Examining  the  backs  of  different  starfishes  with  a  strong  magni- 
fying-glass,  one  will  be  surprised  to  see  the  varied  grouping  of 
the  spines  and  pedicellariae.  At  the  extremity  of  each  arm  is  a 
red  eye-spot,  which  is  sensitive  to  light,  and  a  tube-foot,  which  has 

no  sucker  and  which  is  believed' to 
act  both  as  an  olfactory  and  as  a 
feeling  organ.    The  madreporic  plate 

lies  at  the  angle 
d  of  two  of  the 
arms  or  rays. 
Water  filters  through  the 
madreporic  plate  and 
passes  by  the  stone-canal 
to  the  ring-canal  around 
the  mouth,  and  thence  to 
the  radial  tubes,  one  of 
which  extends  through 
each  arm  and  is  connected 
by  a  branch  with  each 
tube-foot.  At  the  base  of 
each  tube-foot  there  is  a 
globular  reservoir,  or  ampulla.  A  valve  connects  the  tube-foot  and 
ampulla.  When  the  ampulla  is  contracted,  water  is  forced  into  and 
distends  the  tube-foot ;  when  the  ampulla  is  distended,  it  withdraws 
the  water  from  the  tube-foot,  thus  acting  like  a  suction-bulb.  When 
water  is  sent  into  the  tube-feet  they  are  greatly  extended  and  are  then 
placed  against  an  object.  The  water  being  then  withdrawn  through 
the  ampullae,  a  vacuum  is  formed,  and  the  suckers  are  tightly  at- 
tached. By  the  alternating  movements  of  the  ambulacra  the 
animal  is  dragged  slowly  along  and  moves  with  a  gliding  motion. 
It  does  not  deviate  from  a  straight  path,  going  over  elevations 
or  through  depressions  without  turning  aside;  its  body  con- 
forms to  the  irregularities  of  the  road  and  never  bridges  over 
spaces.  The  stomach  extends  a  little  way  into  the  arms,  and  a 
short  intestine  leads  to  the  excretory  opening  in  the  center  of  the 
back.     Starfishes  are  carnivorous  and  voracious,  and  are  partic- 


Diagram  of  water-vascular  system  of  a  starfish:  a, 
madrepoi-ite ;  b,  stone-canal ;  c,  ring-canal ;  d,  radial  canals ; 
e,  ampullse  ;  /,  ambulacra. 


STARFISHES  207 

iilarly  destructive  to  oyster-beds.  The  animal  fastens  itself  to  a 
bivalve,  and  protrudes  a  part  of  its  stomach,  with  which  it  envel- 
ops its  prey  and  slowly  sucks  it  out  of  its  shell.  When  feeding 
on  small  moUusks  they  take  them  into  the  stomach  directly. 
Starfishes  regain  by  natural  growth  parts  of  the  body  which 
may  be  lost.  Sometimes  the  animal  throws  off  an  arm  to  escape 
capture,  and  self-mutilation  also  occurs  where  unfavorable  con- 
ditions exist.  Oystermen  formerly  were  ignorant  of  the  star- 
fish's wonderful  powers  of  regeneration,  and  were  in  the  habit 
of  cutting  up  those  captured  in  their  forks  and  throwing  them 
overboard,  thus  increasing  the  number  instead  of  destroying  their 
enemies,  as  each  arm  with  a  piece  of  the  body  attached  to  it 
will,  it  is  said,  become  a  new  individual.  This  tenacity  of  life 
makes  starfishes  difficult  to  destroy,  and  they  are  exceedingly 
plentiful  in  all  seas.  One  naturalist  speaks  of  seeing  on  the 
coast  of  Maine  a  bed  of  starfishes  which  extended  several  miles 
and  covered  the  bottom  so  closely  that  he  picked  sixty  individ- 
uals off  a  small  stone.  On  the  northern  shores  of  the  Pacific 
coast  they  abound  in  great  variety,  and  some  are  of  unusual  size. 
Asterias  giganfea  of  this  region  measures  two  feet  across.  Another 
species,  PJiyncopodia  heUanthoides,  measures  a  yard  in  diameter, 
and  has  twenty  or  more  arms.  The  most  common  species  of  the 
Atlantic  coast  are  Asterias  vulgaris  and  A.  Forhesii;  the  former 
ranges  from  Long  Island  northward,  the  latter  from  Massachu- 
setts to  Florida.  These  are  the  species  particularly  destructive 
to  oyster-beds.  Asterias  vulgaris  sometimes  grows  to  be  fifteen 
inches  in  diameter ;  from  this,  which  is  perhaps  the  largest,  are 
found  starfishes  of  all  sizes  down  to  the  very  small  Crihrella. 
They  inhabit  all  varieties  of  bottoms,  from  low-water  mark  to 
deep  water.  They  are  not  always  abundant  in  the .  same  place, 
but  seem  to  move  about. 

Some  oystermen  believe  that  the  starfishes  get  into  masses  like 
a  ball  and  are  rolled  along  by  the  tide.  This  idea  comes  from 
the  fact  that  an  oyster-bed  may  be  free  from  them  one  day  and 
the  next  be  covered  by  these  pests.  To  get  rid  of  them  the  beds 
are  swept  over  with  a  tangle,  which  is  an  iron  bar  holding  swabs 
of  raveled  rope.     The  spines  of  the  starfish  are  caught  in  the 


208  MARINE  INVERTEBRATES 

tangle,  and  often  hundreds  are  brought  up  in  one  haul  and  are 
then  killed  by  steaming. 

The  anatomical  system  of  the  starfish  is  easily  traced  by  cut- 
ting off,  with  scissors,  the  skin  from  the  dorsal  surface  of  the 
disk,  and  also  cutting  a  slit  down  one  of  the  arms.  In  the  center 
of  the  body  will  be  seen  the  upper  part  of  the  stomach,  a  small 
star-like  spot,  from  which  radiate  five  branches,  which  divide  and 
lead  into  the  much-ramified,  plume-like  organs  which  extend 
through  the  arms.  These  are  the  pyloric  caeca,  whose  function  is 
to  secrete  the  digestive  fluids.  The  much-folded  stomach  occu- 
pies the  greater  part  of  the  central  space,  its  large  convolutions 
showing  on  top.  The  mouth  connects  with  the  stomach  on  the 
ventral  side.  By  turning  back  the  skin  from  the  arm,  small  fili- 
form processes  can  in  some  large  species  be  seen ;  these  are  the 
dermal  branchiae,  or  breathing-organs,  which  may  either  project 
through  pores  in  the  skin  between  the  ossicles  or  be  entirely  re- 
tracted. If  the  pyloric  cseca  be  laid  back,  one  can  see  the  rib- 
like arrangement  of  the  ambulacral  ossicles,  and  also  the  ampuUae, 
which  lie  between  the  ossicles  on  each  side  of  the  ridge.  If  an 
ampulla  be  inflated  and  then  pressed,  the  corresponding  tube-foot 
will  be  seen  to  extend.  To  follow  successfully  the  water- vascular 
system,  beginning  in  the  madreporic  plate  and  extending  through 
the  stone-canal  to  the  ring-canal  around  the  mouth  and  thence 
through  the  arms,  requires  a  strong  glass  and  more  skilful  manip- 
ulation. 

ORDER  PHANEROZONIA 

Family  porcellanasteridje. 

Genus  Ctenodiscus  (Plate  LII) 

C,  corniculatus.  Pentagonal ;  about  two  and  a  half  inches  in  diam- 
eter ;  the  body  flat,  with  wide  marginal  plates,  giving  a  flat  edge  to  the 
rather  long,  pointed  arms  ;  madreporic  plate  large  j  color  greenish ;  am- 
bulacra without  suckers,  seeming  to  be  adapted  to  pushing  through  soft 
mud  rather  than  dragging  over  hard  surfaces.  It  lives  in  deep  water  on 
muddy  bottoms  and  ranges  from  Massachusetts  to  Greenland.  When 
dredged  the  animal  is  usually  found  to  be  filled  with  soft  mud. 

Family  astropectinid^ 
In  this  family  there  are  only  two  rows  of  tube-feet;  the  rays 
end  in  sharp  points  and  have  large  ossicles  on  the  margins. 


STARFISHES  209 

Genus  Astropecten 

A*  aHicularis,  The  body  is  flat  and  smooth ;  the  rays  sharply 
pointed  and  conspicuously  bordered  with  marginal  ossicles  and  fringed 
with  short  spines;  two  rows  of  ambulacral  feet;  color  rich  purple. 
Found  in  shallow  waters  of  South  Atlantic  coast  on  sandy  bottoms. 
(Plate  LII.) 

Genus  Psilaster 

P,  florae.  Diameter  four  to  five  inches ;  arms  sharply  pointed  and 
conspicuously  bordered  with  large  ossicles ;  body  flat,  with  smooth  sur- 
face, the  ossicles  seeming  like  mosaic ;  bright  pinkish  flesh-color.  It 
occurs  in  deep  water  off  the  eastern  coast  as  far  south  as  New  Jersey. 

Genus  Luidia 

This  genus  of  starfishes  is  celebrated,  for  its  peculiar  habit  of 
breaking  in  pieces  when  taken  from  the  water,  and  therefore  good 
specimens  are  almost  impossible  to  obtain. 

£.  senegalensis.  Twelve  to  fourteen  inches  across ;  arms  long  and 
narrow,  tapering  to  a  point  and  fringed  on  the  edges  with  spines ;  sur- 
face rather  smooth,  showing  the  separation  of  the  ossicles ;  color  almost 
white,  with  dark  line  running  through  the  center  of  each  arm ;  usually 
nine  arms.  Found  in  shallow  water  on  the  coasts  of  Florida  and  the 
Gulf  of  Mexico. 

L,  clathrata.  Four  to  five  inches  across;  light-colored;  with  a 
fringe  of  spines  on  the  margins  of  the  arms,  which  taper  to  a  point; 
two  rows  of  ambulacra.  It  is  found  from  New  Jersey  southward,  and  is 
one  of  the  most  common  starfishes  on  the  sandy  beaches  of  North  and 
South  Carolina.     (Plate  LII.) 

L,  alternata.  Upper  surface  purplish,  with  irregular  yellowish  bands 
on  the  arms;  under  surface  yellow.  Found  in  shallow  water  on  the 
Florida  coast. 

Family  pentagonasterid^: 

Genus  Mediaster 

M,  cequalis.  Body  flat ;  the  five  rays  equal  or  exceed  in  length  the 
diameter  of  the  disk  ;  margins  have  double  row  of  large  plates ;  surface 
covered  with  granules,  which  are  easily  rubbed  off ;  bright  red  above, 
pale  orange  below;  diameter  four  inches.  Common  on  the  coasts  of 
Oregon  and  California. 

Family  antheneid^ 

Genus  Hippasteria 

JET,  phrygiana.     This  beautiful  starfish  lives  in  deep  water,  but  is 
sometimes  thrown  up  on  the  beach,  and  ranges  from  Cape  Cod  north- 
u 


210  MARINE  INVERTEBRATES 

ward.  It  has  a  large,  pentagonal,  bright-scarlet  disk,  five  to  six  inches 
in  diameter,  with  arms  rather  long  a,nd  pointed.  The  upper  side  is  raised 
and  cushion-like,  and  is  covered  with  blunt  spines;  the  margins  have 
larger  spines  of  the  same  shape.  The  pedicellarise  are  sessile  and  so 
long  and  large  as  to  be  easily  seen  with  the  naked  eye.     (Plate  LII.) 

Family  pentacerotid^ 

Genus  I^entaceros 

I*,  occidentalism  Pentagonal;  eight  to  twelve  inches  in  diameter; 
ossicles  a  network  of  rod-like  plates,  with  prominent  spines  at  the  points 
of  union ;  body  inflated  in  the  center  and  running  in  wedge-like  form 
to  the  ends  of  the  rather  long  and  narrow  arms ;  the  upper  lines  of 
the  ridges  have  spines  more  prominent  than  those  on  the  rest  of  the 
body ;  the  spines  of  the  larger  specimens  are  more  like  large  warts  or 
small  hemispheres.     Found  on  the  Lower  California  coast. 

P,  reticularis.  This  starfish  is  the  largest  species  on  our  coasts.  It 
is  common  in  southern  Florida  close  to  the  shore.  The  body  is  three 
to  four  inches  thick,  fiat  on  the  oral  surface,  but  raised  on  the  upper 
side,  and  tapers  down  in  wedge-like  form  to  the  points  of  the  short  arms. 
The  prominent  blunt  spines  which  cover  its  surface  are  arranged  in  a 
somewhat  regular  net-like  order,  and  the  sharp-edged  margins  have  an 
even  row  of  larger  spines  of  the  same  form.  The  madreporic  plate  is 
nearly  in  the  center  of  the  disk,  and  is  quite  conspicuous,  being  bordered 
with  a  circle  of  small  spines.  Its  color  is  dull  yellow,  and  its  size  often 
a  foot  or  more  in  diameter.  It  is  the  large  starfish  so  often  seen  in  curi- 
osity-shops.    (Plate  LII.) 

Genus  Nidorella 

N,  ar^nata.  This  very  curious  pentagonal  species,  found  on  the 
California  coast,  is  five  to  six  inches  in  diameter  and  red  in  color.  The 
upper  surface  is  raised  and  covered  with  thick,  pointed  spines  one  half  of  an 
inch  to  one  inch  long,  arranged  in  lines,  but  not  crowded.  The  ossicles 
on  the  margins  are  large ;  some  of  them  are  hemispherical  and  bear 
large  spines.  Smaller  spines  border  the  under  edge  of  the  margins. 
(Plate  LIII.) 

Family  asteeinidje 

The  starfishes  of  this  family  are  pentagonal,  with  a  large  body 
and  short  arms.  The  disk  is  more  or  less  elevated  in  the  center, 
and  the  edges  are  sharp.  There  are  two  rows  of  ambulacra.  The 
ossicles  are  notched  and  overlapping.  The  family  is  confined  .to 
temperate  and  tropical  waters. 

Genus  Asterina 

A,  folium.  Small,  pentagonal,  swollen  (gibbous).  Found  on  the 
Florida  coast. 


PLATE   LII. 


Ctenodiscus  crispatus.  Astropecten  articularis. 

Luidia  clathrata,  Hippasteria  phrygiana. 

Pentaceros  reticularis. 


PLATE   LIII. 


Nidorella  armata. 
Solaster  decemradiata. 


Asterina  miniata. 
Crossaster  papposus. 


STARFISHES  211 

A.  miniata.  Pentagonal;  somewhat  raised  in  center  j  about  one 
and  a  half  inches  across ;  edges  sharp.  Found  on  the  California  coast 
close  to  shore.     (Plate  LIII.) 

ORDER  CRYPTOZONIA 
Family  solasterid^ 

Genus  Solaster 

S,  endeca.  Dark  red  in  color ;  nine  to  eleven  arms,  which  are  shorter 
than  the  breadth  of  the  disk  -,  diameter  of  disk  about  five  inches ;  two 
rows  of  ambulacra ;  surface  rather  smooth.  Common  on  the  coast  of 
Maine,  and  found  from  Cape  Cod  to  Newfoundland  below  low-water 
mark. 

S,  decetnradiata.  This  species  is  common  on  the  North  Pacific 
coast.  It  has  ten  arms,  which  are  about  twice  the  length  of  the  diameter 
of  the  body,  the  whole  body  being  about  a  foot  across.     (Plate  LIII.) 

Genus  Crossaster 

C.  papposus.  Twelve  to  fifteen  arms,  half  as  long  as  the  breadth 
of  the  body  J  upper  surface  an  open  network  of  calcareous  rods,  or 
ossicles;  at  their  points  of  union  are  club-shaped  tubercles  bearing 
tufts  of  smaller  spines ;  concentric  lines  and  spots  of  red  and  purple 
over  the  spiny  upper  surface ;  color  light  underneath.  Common  on  the 
New  England  coast.     (Plate  LIII.) 

Family  echinasteridje 

Genus  Cribrella 

C,  sanguinolenta.  This  species  is  abundant  north  of  Cape  Cod  and 
is  found  of  all  sizes  from  half  an  inch  to  two  inches  in  diameter  and  of 
various  colors — ^  purple,  orange,  red,  yellow,  flesh-color,  etc.  It  has  five 
round  arms,  generally  about  four  times  as  long  as  the  breadth  of  the 
disk.  The  ends  are  often  turned  upward.  It  is  covered  with  crowded 
short  spines,  like  little  warts,  which  give  it  a  nearly  smooth  surface.  It  has 
two  rows  of  ambulacra.  It  moves  with  two  of  its  arms  turned  forward, 
as  if  they  were  dragging  the  other  three  behind  them.  Unlike  most 
species,  the  young  are  not  free-swimming,  but  the  eggs  are  carried  around 
the  mouth  of  the  mother,  and  the  young  are  retained  there  until  they  are 
capable  of  taking  care  of  themselves.     (Plate  LIV.) 

Genus  Echinasfer 

E,  sentus.  This  species  occurs  close  to  shore  in  the  waters  of  Florida 
and  is  perhaps  the  most  commonly  observed  species  on  the  beach.  It 
extends  as  far  north  as  New  Jersey.  It  is  purplish  in  color,  and  about 
four  and  a  half  inches  in  diameter,  with  two  rows  of  ambulacra,  five 
arms,  and  a  surface  rough  with  spines. 


212  MARINE  INVERTEBRATES 

Family  heliasterid^ 

Genus  Heliaster 

H,  multiradiata.  Spines  on  the  upper  surface  of  rays  in  five  rows, 
but  close  to  the  disk  proper  become  reduced  to  one  row.  Found  on 
the  coasts  of  Lower  California  and  Mexico.    (Plate  LIV.) 

Family  asteriid^ 

The  AsteriidcB  have  the  following  cbaracteristics  :  four  rows 

of   tube-feet;    ossicles    small    and   unequal;    spines  isolated   or 

grouped ;  pedicellariae  of  two  forms,  forceps-like  and  scissors-like 

respectively.     They  include  the  very  common  forms  found  on  all 

beaches. 

Genus  Asterias 

A,  vulgaris.  The  common  starfish  of  the  Atlantic  coast,  from  Long 
Island  Sound  to  Labrador.  It  occurs  at  low-water  mark  and  extends  into 
deep  water.  It  has  five  arms,  which  taper  to  a  point.  Large  specimens 
measure  fifteen  inches  across.  The  upper  surface  is  rough,  being  cov- 
ered with  short  spines,  which  are  largest  and  thickest  at  the  edges  of  the 
rays,  and  surrounding  them  are  the  pedicellarise.  The  color  varies  from 
pink,  yellow,  and  brown  to  purple. 

A*  Forbesii,  The  common  starfish  of  the  Atlantic  coast,  from  Massa- 
chusetts Bay  to  the  Gulf  of  Mexico.  This  species  resembles  very  closely 
A.  vulgaris,  but  can  be  distinguished  from  it  by  the  madreporic  plate, 
which  is  bright  orange,  while  in  the  former  it  has  the  same  color  as  the 
animal ;  also  the  arms  are  a  little  swollen  at  the  base  and  terminate  more 
bluntly.  These  two  species  are  very  destructive  to  oyster-beds,  espe- 
cially where  their  ranges  overlap.  It  is  computed  that  they  destroy 
annually  two  hundred  thousand  dollars'  worth  of  oysters.  Vast  numbers 
congregate  where  the  feeding-ground  is  good,  and  move  in  long  lines  from 
place  to  place.  The  oystermen  dredge  over  the  beds  and  bring  them 
up  in  thousands,  then  steam  them  or  throw  them  on  the  shore  above 
high- water  mark.    (Plate  LIV.) 

A,  ochracea.  The  common  starfish  of  the  Pacific  coast,  from  Sitka  to 
San  Diego.  Five  rays,  each  hardly  twice  as  long  as  the  diameter  of 
the  body ;  spines  running  irregularly  over  the  surface,  but  forming  a 
pentagon  at  the  middle  of  the  disk  and  inclosing  the  madreporic  plate  ; 
diameter  eight  inches.  It  is  very  common  near  San  Francisco  on  rocks 
at  low- water  mark.     (Plate  LIV.) 

A.  gigantea.  Body  very  large  and  swollen;  six  rays,  somewhat  less 
in  length  than  twice  the  diameter  of  the  disk ;  aboral  surface  covered 
with  numerous  short,  blunt,  equidistant  spines  of  uniform  size  and 
regularly  distributed ;  spines  contracted  at  the  base  and  striated ;  diam- 
eter two  feet.    Found  on  the  California  coast. 


PLATE  LIV. 


Cribrella  sanguinolenta. 
Asterias  Forbesii. 


Heliaster  multiradiata. 
Asterias  ochracea. 


TABLE  SHOWING  THE  CLASSIFICATION  OF  THE  BRITTLE-STAES 
DESCRIBED  IN  THIS  CHAPTER. 

Class 
OPHIUROIDEA 

(Brittle-stars) 


Orders 
EUEYALIDA 

(Skin  without  plates;  arms  simple  or 
branched,  and  capable  of  being  rolled 
up) 


OPHIURIDA 

(Skin  with  plates) 


Genera 
Astrophyton 

Ophiopholis 
Aniphiura 

Ophiocoma 

OpMothrix 


Species 
A,  Agassizii 


O,  aculeata 
A.  squamata 
O,  riisei 
O,  cetJiiops 
O.  Alexandri 
O.  angiilata 


213 


CLASS   OPHIUROIDEA 

BRITTLE-STARS 

THE  ophiurans,  or  brittle-stars,  differ  from  the  starfishes  in 
having  the  arms  quite  distinct  from  the  body.  In  starfishes 
the  arms  are  extensions  of  the  body,  and  the  viscera  extend  part- 
way into  them,  while  in  ophiurans  the  body  is  a  central  disk,  with 
the  five  narrow  arms  attached  to  its  margin.  In  form  they  sug- 
gest a  spider,  and  sometimes  are  called  sea-spiders.  The  name 
brittle-star  is  also  descriptive,  since  they  break  off  their  limbs 
readily.  The  arms  are  narrow,  taper  to  a  point,  usually  curl  at 
the  ends,  and  have  no  ambulacral  grooves,  but  are  completely 
covered  with  bare  calcareous  plates  (except  in  the  first  order,  where 
they  have  a  skin  and  no  plates).  The  ambulacra  are  small  spines 
without  suckers,  which  emanate  from  the  sides  or  margins  of  the 
arms  and  do  not  serve  for  walking.  The  madreporic  plate  is  on 
the  ventral  surface,  in  one  of  the  circular  shields  which  surround 
the  mouth.  The  alimentary  canal  ends  blindly.  The  egg-sacs 
lie  between  the  arms  and  open  by  slits  on  the  under  side,  close  to 
the  arms,  where  they  join  the  disk.  Water  fiows  in  and  out  of 
these  pouches,  which  are  thought  to  have  also  respiratory  and 
excretory  functions.  No  eye-specks  have  been  found,  but  they 
must  exist,  since  the  animal  is  sensible  to  approaching  danger  and 
quickly  retreats.  The  ophiurans  are  more  active  than  starfishes, 
moving  by  wriggling,  and  clambering  with  their  arms.  They  are 
shy  and  hard  to  find,  and  it  is  difficult  to  capture  a  whole  one, 
since  they  throw  off  pieces  of  their  arms  at  the  least  alarm.  Often 
they  completely  dismember  themselves,  an  action  which  does  them 
no  permanent  injury,  since  they  reproduce  lost  parts.  They  are 
more  commonly  inhabitants  of  deep  than  of  shallow  waters,  and 
are  brought  up  from  the  bottom  in  dredges  in  great  numbers. 

214 


BRITTLE-STARS  215 

Some  species  may  be  found  near  low-water  mark  nnder  stones 
and  in  clusters  of  mussels,  and  often  in  seaweeds,  thrown  up 
from  deep  water,  on  the  shore. 

ORDER  EURYALIDA 

Genus  Astrophytofi  (Plate  LV) 

A.  Agassizii,  This  very  singular  ophiuran  is  commonly  called  the 
basket-fish,  from  its  resemblance  to  a  basket  when  the  tentacles  are 
rolled  up.  Its  body  is  covered  with  skin  instead  of  calcareous  plates. 
The  body  is  thick  and  somewhat  circular  in  form,  with  elevated  radi- 
ating ridges  on  the  upper  side,  and  the  skin  is  marked  off  in  star-like 
divisions.  From  the  margin  of  the  body  extend  five  arms,  which  at 
once  divide  in  a  forking  manner ;  each  section  again  divides,  and  this 
division  in  pairs  (dichotomous  division)  continues  until  the  ends  of  the 
arms  have  become  very  numerous  and  attenuated.  The  arms  are  carried 
curled  up  or  straight  at  will.  In  moving,  the  animal  seems  to  walk  on 
these  branches  as  if  on  tiptoe,  and  in  this  position  it  forms  a  kind  of 
net  which  entraps  prey.  The  arms  and  prominent  parts  of  the  disk  are 
yeUow,  and  the  depressed  or  membranous  parts  brown.  AstropJiyton  is 
six  to  eighteen  inches  in  diameter.  It  is  found  off  the  northern  New 
England  coast. 

ORDER   OPHIURIDA 

Genus  Ophiopholis 

O,  aculeata.  This  is  a  common  species,  found  in  shallow  water  on 
the  North  Atlantic  coast.  A  similar  or  perhaps  identical  species  occurs 
on  the  North  Pacific  coast.  It  is  spotted  purple  or  variegated  in  color. 
The  upper  surface  of  the  body  is  covered  with  plates  variously  arranged, 
sometimes  in  the  shape  of  a  star,  and  each  one  is  surrounded  with  small 
spines.  The  under  side  of  the  egg-sacs  is  covered  with  small  spines. 
These  sacs  open  by  slits  on  each  side  next  the  arms,  and  have  a  rounded 
appearance,  bulging  out  between  the  arms.  The  arms,  which  are  long 
and  attenuated  at  the  ends,  have  on  the  upper  side  transverse  oval  plates 
surrounded  by  a  border  of  flat,  roundish  granules.  Sometimes  the 
plates  are  divided  into  two  or  three  pieces,  when  they  are  similarly  bor- 
dered with  granules.  The  arms  are  fringed  with  rows  of  thick,  com- 
pressed, obtuse  spines,  generally  six  in  each  row.  The  under  sides  of  the 
arms  have  large  quadrangular  plates  slightly  separated  from  one  another 
and  extending  across  the  whole  surface  in  regular,  even  rows. 
(Plate  LV.) 

Genus  Afn2)hiura 

A.  squamata.  This  very  delicate  species,  found  on  shelly  bottoms 
below  low-water  mark  from  New  Jersey  northward,  has  a  body  less 
than  one  quarter  of  an  inch  in  diameter,  with  arms  two  inches  or  more 


216  MARINE  INVERTEBRATES 

in  length  and  thread-like  in  size.  These  long,  slender  arms  have,  on 
both  the  upper  and  under  surfaces,  a  row  of  overlapping  plates,  and  are 
fringed  with  small  spines,  three  in  a  row.  The  color  is  gray  or  whitish, 
sometimes  marked  with  darker  gray  or  brown.     (Plate  LV.) 

Genus  Ophiocoma 

O,  riisei,  O,  cethiops,  O.  Alexandri,  These  animals  have  long 
spines  on  the  sides  of  the  arms,  which  give  them  a  bnshy  appearance. 
The  surface  of  the  body  is  granulated,  but  the  arms  are  covered  with 
wide  plates.  Their  color  is  brown  above  and  light  beneath.  0.  riisei  is 
found  at  Key  West,  the  other  two  species  on  the  coast  of  Lower 
Cahfornia.     (Plate  LV.) 

Genus  Ophiothrix 

O.  angulata.  Body  covered  with  short,  rough  spines  j  egg-sacs 
conspicuous  and  extend  like  lobes  between  the  arms ;  rays  narrow  and 
thickly  beset  with  long  spines,  which  are  serrated  on  the  edges  and  ends. 
Found  on  the  Florida  coast.     (Plate  LV.) 


PLATE  LV. 


Astrophyton. 
Ophiocoma  oethiops. 
Ophiothrix  angulata. 


Ophiopholis  aculeata. 
Ophiocoma  Alexandri. 
Amphiura  squamata. 


TABLE    SHOWING    THE    CLASSIFICATION    OF    THE    ECHINOIDEA 
DESCRIBED  IN  THIS  CHAPTER 

Class 
ECHINOIDEA 

Order  DESMOSTICHA  or  REGULARIA 

Shell  usually  globular ;  mouth  and  anus  -polar  ;  lantern  of  Aristotle  present) 


Families 

CIDARIDiE 

ARBACIADJE 
DIADEMATIDJE 

ECHINOMETRIDiE 
ECHINIDiE 


Genera 

/Cidaris 
DorocidaHs 


Porocidaris 
( Arbacia 
\  Ccelopleurus 

Diadema 
r  Echinonietra 

I  Strongylocentrotus 

( Echinus 

I  Toxopneustes 


Species 

C  tribuloides 
D,  papillota 
D,  Blakei 
JP,  sharreri 
A.  punctulata 

C.  floridanus 

D.  setosum 

E.  subangularis 
S.  drobachiensis 

I S,  purpuratus 
S.  franciscanus 
E,  gracilis 
T.  variegatus 


Order  CLYPEASTROIDEA 
(Corona  or  shell  a  more  or  less  flattened  disk;   anus  excentric ;   lantern  of  Aristotle  present) 


ECHINANTHID^ 


SCUTELLIDiE 


^  Clypeaster 
i  Echinanthus 

{Echin  arachnitis 
Mellita 
Encojye 


C.  ravenellii 
E,  rosacetis 
E,  parma 
E,  excentriciis 
M,  testudinata 
E,  ^nichelini 


Order  SPATANGOIDEA  or    PETALOSTICHA 

(Heart-shaped;  mouth  and  excretory  opening  excentric;  no  lantern  of  Aristotle) 


{Moira 
Lovenia 
Schizaster 
Metalia 
Brissopsis 


M,  atropos 
L,  cordiforrnis 
S,  fragilis 
M,  pectoralis 
B,  lyrifera 


217 


CLASS   ECHINOIDEA 

SEA-URCHINS,  CAKE-URCHINS,  HEART-URCHINS 

ORDER  DESMOSTICHA 

SEA-URCHINS 

THE  shell  of  a  sea-nrcMu  consists  of  many  calcareous  plates, 
or  ossicles,  fitted  closely  together  and  forming  a  contin- 
uous exoskeleton.  The  plates  are  so  united  that  externally  the 
marks  of  juncture  are  not  perceptible,  but  on  the  interior  the 
shape  of  these  plates  is  well  defined.  In  examining  such  a  shell, 
or  test  (they  abound  on  the  beach),  it  will  be  seen  that  its  surface 
is  covered  with  numerous  hemispherical  projections  or  knobs, 
which  are  grouped  in  double  rows  and  run  in  meridional  lines 
from  one  pole  to  the  other  of  the  more  or  less  spherical  body, 
separating  it  into  ten  divisions.  Five  of  these  divisions  have 
perforations,  or  small  pores  in  the  plates  of  the  shell,  and  are 
called  the  cmibulacrcd  zones  or  areas,  because  through  these  pores 
pass  the  small  tubes,  in  the  living  animal,  which  connect  the 
tube-feet,  or  amhulacra,  with  the  radial  water-canals  and  the  am- 
pullm  (see  page  206).  The  wide  spaces  between  these  double 
rows  of  pores  are  called  the  interamhilacral  zones  or  areas.  The 
ten  spaces  diverge  from  the  ijeristome,  or  soft  part  around  the 
mouth,  in  the  center  of  the  lower  surface,  and  converge  in 
the  small  area  at  the  top  or  aboral  side.  In  the  center  of  this 
small  circular  dorsal  space  is  the  excretory  opening,  and  sur- 
rounding it  are  ten  plates,  five  of  which  have  openings  into  the 
egg-sacs.  One  of  them  is  larger  than  the  others,  and  is  modified 
to  form  the  madreporic  plate.  The  other  five  plates  have  eye- 
specks.  The  ambulacral  zones  terminate  at  these  ocular  plates. 
The  numerous   spines  which  cover  the  animal  are  of  three 

218 


SEA-URCHINS 


219 


kinds,  and  proceed  from  the  knobs  on  the  exoskeleton,  over 
which  they  fit,  forming  ball-and-socket  joints,  which  enable  them 
to  move  in  any  direction.  The  long  spines  are  ribbed,  and  seem 
to  have  no  other  function  than  that  of  protection.  The  second 
set,  the  pedicellarice,  are  very  peculiar  small  organs  scattered  over 
the  surface  in  great  numbers,  and  consisting  of  a  head  bearing 
three  bill-like  blades  mounted  on  a  long,  flexible  stalk.     The  office 


Ini.cuni 


Am-L 


/nt.cLmJb 


Test  of  sea-urchin,  witli  the  spines  removed  to  show  the  arrangement  of  the 
plates,  lateral  view :  Amb,  ambulacral  zone  with  its  perforated  plates ;  Ap,  apical 
(aboral)  pole ;  Int.  amb.,  interambulacral  zones.     (From  Bronn's  "  Thierreich.") 


of  some  of  the  pedicellariaB  is  to  remove  waste  from  the  excretory 
opening;  this  is  passed  down  regular  lines  and  dropped  into 
the  water,  thus  keeping  the  body  clean.  Others  are  constantly 
opening  and  shutting  their  forks,  reaching  in  all  directions  and 
grasping  and  removing  anything  which  may  have  become  entan- 
gled in  the  spines.  They  also  capture  floating  bits  of  seaweed, 
which  they  drag  over  the  body  to  conceal  it.  A  third  set  of 
projections  are  the  spJic^ridia,  small  globular  bodies  said  to  be 
connected  with  perception. 

The  spines  vary  greatly  in  size,  number,  and  form  in  different 
species,  and  are  such  conspicuous  features  as  to  make  the  identi- 
fication of  species  easy.     In  some  the  spines  are  solid  and  fluted  j 


220  MARINE  INVERTEBRATES 

in  others  they  are  hollow,  sharp,  and  brittle  j  again  in  others  they 
are  short  and  silky,  or  very  long  and  serrated,  and  so  on.  In 
one  species  they  are  so  broad  and  flat  as  to  resemble  little  sails. 
(See  Borocidaris.)     (Plate  LVI.) 

The  mouth,  over  which  five  long  teeth  project,  is  a  part  of  Aris- 
totle's lantern,  which  forms  a  curious  and  prominent  feature  in 
the  center  of  the  lower  surface.  Ten  tentacles,  like  large  tube- 
feet  without  suckers,  lie  around  the  mouth.  The  alimentary 
canal,  starting  in  Aristotle's  lantern,  winds  in  two  and  a  half 
coils  around  the  inside  of  the  shell,  supported  by  mesenteries, 
and  terminates  in  the  excretory  opening  on  the  aboral  surface. 
The  sea-urchin  has  also  a  water-vascular  system  similar  to  that 
of  starfishes  (page  206).  When  the  tube-feet  are  distended  they 
project  beyond  the  spines,  and  enable  the  animal  to  move  slowly 
about ;  but  sea-urchins  are  less  active  than  starfishes,  and 
although  they  are  so  well  protected  by  spines  and  have  few 
enemies  after  maturity,  they  lie  in  sluggish  idleness  in  secluded 
places,  and  for  further  concealment  often  cover  themselves  with 
seaweeds  or  stones. 

The  sea-urchin  has  a  nervT)us  system,  which  starts  in  a  ring 
around  the  mouth,  ramifies  through  the  body,  and  terminates  in 
the  eye-plates.  The  tube-feet  and  all  the  spines  are  under  nervous 
as  well  as  muscular  control.  Egg-sacs  he  under  the  apex  of  the 
shell  and  open  by  separate  ducts  into  the  five  plates  on  the  small 
upper  disk.  Through  these  the  eggs  are  discharged  into  the 
water,  where  they  become  free-swimming  larvge,  called  Pliifens. 
This  immature  sea-urchin  (Pluteus)  undergoes  several  curious 
transformations  in  the  course  of  its  development,  and  does  not  in 
any  way  resemble  the  mature  animal.  In  spring  the  apical  disk 
of  the  females  will  often  be  found  covered  with  orange-colored 
ova,  and  that  of  the  males  with  white  sperms.  In  the  growth  of 
the  animal,  in  its  mature  form,  the  shell  enlarges  by  accretions 
of  lime  on  the  individual  plates,  or  ossicles,  of  the  exoskeleton, 
and  by  new  plates  formed  around  the  apical  disk.  Sea-urchins 
are  compared  to  starfishes  folded  over,  the  eye-specks  on  the  ends 
of  the  rays  meeting  in  a  small  area  around  the  excretory  opening, 
the  ambulacra  following  spherical  lines  and  leaving  the  mouth,  as 
before,  on  the  ventral  side. 


SEA-URCHINS  221 

The  Uchinoidea  present  great  differences  in  shape,  being  more 
or  less  spherical,  oval,  discoid,  and  heart-shaped.  These  varia- 
tions are  associated  with  the  differences  of  internal  structure, 
the  openings  of  the  digestive  tract  being  at  the  opposite  poles  in 
the  spherical  and  oval  forms,  but  excentric  in  the  disk-  and  heart- 
shaped  species.  The  sea-urchins  are  grouped  in  three  orders  in 
accordance  with  these  variations.  All  are  characterized  by  the 
absence  of  arms,  by  having  the  calcareous  plates  immovably 
united  to  form  a  firm  test,  and  by  the  great  development  of  the 
movable  spines  upon  the  plates. 

Sea-urchins  are  sometimes  called  sea-eggs,  perhaps  from  their 
shape,  but  possibly  from  the  edible  quality  of  some  species,  which 
are  eaten  by  the  natives  of  the  shore,  who  take  them  at  the 
spawning  season,  when  the  egg-sacs  are  distended.  They  are  gre- 
garious, and  frequently  are  so  crowded  together  as  literally  to  pave 
the  surface  of  rocks  and  the  bottoms  of  tide-pools  in  sheltered 
places.  The  following  is  quoted  from  A.  Agassiz  :  "  Many  of  the 
BesmosticJia  along  coasts  exposed  to  the  action  of  the  waves  live 
in  cavities  which  they  hollow  out  of  the  solid  rock.  This  they 
do,  not  by  means  of  any  solvent,  but  by  mere  mechanical  action. 
They  chisel  out  with  their  teeth  the  solid  rock  by  incessant  turn- 
ing round  and  round,  and  keep  their  cave,  where  they  are  fre- 
quently prisoners  for  the  rest  of  their  existence,  up  to  the  size 
required  by  the  growth  of  their  test  and  spines,  by  constant 
gnawing.  On  the  coast  of  California  the  common  Sfrongylocen- 
trotus  purptiratiis  occurs  in  this  way.  We  find  long  tracts  of 
shore,  where  this  sea-urchin  is  common,  completely  honeycombed 
and  pitted  by  cavities  and  depressions  in  which  they  seek  shelter 
against  the  powerful  surf  continually  beating  against  the  rocks. 
The  same  species  does  not  excavate  in  sheltered  places,  where  the 
sea-urchins  can  find  protection  between  the  interstices  of  large 
fragments  of  rock  or  ledges  more  or  less  sheltered  from  the 
more  direct  action  of  the  open  sea." 

Sea-urchins  in  cavities  of  granite  rock,  where  the  openings  are 
too  small  for  the  animal  to  get  out,  are  to  be  seen  in  thousands 
on  the  coast  of  France  at  Croisic,  Lower  Loire.  Spines  of  large 
sea-urchins  are  used  as  slate-pencils  by  the  missionaries  in  the 
Pacific  Islands. 


222  MARINE  INVERTEBRATES 

Family  cidarid^ 
Genus  Cidaris 

C,  tribuloides.  Similar  to  Porocidaris  sharreri,  but  with  thicker  and 
stouter  spines.     Found  from  South  Carohna  to  Brazil. 

Genus  Dor o cidaris 

D.  papillota,  A  deep-water  species  which  occurs  off  Chesapeake 
Bay  and  southward.  It  has  slender  spines  with  distinct  longitudinal 
rows  of  serrations,  and  the  spines  are  grouped  in  rosette-like  forms  over 
the  small  spherical  body. 

2>.  Blakei.  This  species  is  very  peculiar  in  having  broad,  fan-shaped 
spines ;  vermilion  in  color.  Found  in  deep  water  in  the  Bahamas  and 
West  Indies.     (Plate  LVII. ) 

Genus  JPorocidaris 

PL  sharreri.  This  species  occurs,  in  deep  water,  off  the  coast  of  North 
Carolina  and  thence  southward  to  the  West  Indies.  The  shell  is  light 
greenish-pink.  The  spines  are  white,  with  brownish-pink  at  the  base, 
pointed,  three  and  a  half  inches  long,  and  surrounded  at  the  base  with 
small,  flat,  triangular,  secondary  spines.     (Plate  LVII.) 

Family  arbaciad^ 

Genus  Arhacia 

A,  punctulata,  A  small  species  found  in  shallow  water  on  shelly 
and  gravelly  bottoms  from  Massachusetts  to  Mexico,  and  common  in 
Long  Island  Sound.  The  shell  is  about  one  inch  in  diameter ;  the  spines 
are  rather  thick  and  one  half  to  three  quarters  of  an  inch  long.  The 
color  varies  from  deep  violet  —  almost  black  —  to  straw-color,  and  the 
spines  are  tipped  with  brown.  The  South  Carolina  species  are  usually 
brick-red  in  the  bare  interambulacral  spaces,  with  darker  sutures,  and 
spines  tipped  with  same  color.  The  animal  walks  by  means  of  its  spines, 
with  a  tilting  motion,  and  advances  quite  rapidly <=     (Plate  LVII. ) 

Genus  Ccelopleurus 

C,  fioridamis.  This  beautiful  sea-urchin  is  taken  on  the  Florida 
reefs.  The  very  brittle  spines  are  one  to  four  inches  long,  and  are 
banded  with  carmine  and  white.  The  shell  has  zones  of  light  chocolate- 
color  alternating  with  orange  and  yellow. 

Family  diadematid^ 
Genus  Diadema 

D,  setosum*  Spines  very  brittle,  and  from  one  to  two  and  a  half 
inches  long;  jet-black.    Found  on  the  Florida  reefs.     (Plate  LVII.) 


Ul>n 


H^^ 


It  ^yf 


■r  i; 


PLATE   LVI. 

Pedicellariae  of  sea-urchins. 
Spines  of  sea-urchins. 


PLATE   LVII. 


Porocidaris  sharreri.  Dorocidaris  Blakei. 

Arbacia  punctulata. 
Diadema  setosTun.  Strongylocentrotus  franciscanus. 


SEA-URCHINS  223 

Family  ECHiNOMETRiDiE 
In  this  family  the  ambulacral  plates  have  several  pairs  of  pores. 

Genus  EcJiinometra 

E,  subangularis.  This  species,  which  ranges  from  South  Carolina 
to  BrazU,  and  is  also  found  in  Bermuda,  is  common  on  mud-flats  and  is 
easily  distinguished  by  its  oblong  or  elliptical  shape.  Its  shell  is  about 
three  inches  long  in  its  widest  portion.  The  spines  are  one  half  of  an 
inch  to  one  inch  long,  thick  at  the  base  and  tapering  to  a  point.  The 
color  is  dark  purplish-green  to  deep  violet  —  almost  black. 


Genus  Strongylocentrotus 

S.  drohachiensis.  This  sea-urchin  (which  bears,  perhaps,  the  longest 
name  in  technical  nomenclature  and  has  no  other,  unless  that  of  ^'  sea- 
egg,"  which  is  applied  indiscriminately  to  all  sea-urchins)  is  a  very  com- 
mon species  in  shallow  waters  of  the  northern  temperate  zones.  It 
extends  as  far  as  New  Jersey  on  the  Atlantic  and  to  the  State  of  Wash- 
ington on  the  Pacific  coast.  Although  it  is  found  as  far  south  as  New 
Jersey,  it  is  there  rare  and  small  j  but  farther  north,  especially  on  the 
coast  of  Maine,  it  is  exceedingly  abundant.  It  is  green  or  greenish- 
purple  in  color,  and  resembles  somewhat  a  large  chestnut-bur.  The 
body  is  circular,  somewhat  depressed  (but  of  variable  thickness),  and 
about  two  inches  in  diameter.  The  spines  are  moderately  slender  and 
longitudinally  striated.  It  feeds  partly  on  diatoms  and  other  small 
algSB,  which  it  cuts  from  the  rocks  with  its  sharp  teeth.  It  also  devours 
dead  fishes,  bones  and  all,  and  in  return  is  swallowed  whole  by  the  wolf- 
fish  and  other  large  fishes.  It  moves  by  means  of  the  tube-feet  on  its 
oral  surface,  slowly  dragging  itself  along,  and  frequently  is  seen  with 
seaweed,  a  stone,  or  some  other  substance  on  its  back,  which  it  places 
there  with  its  pedicellarise  for  the  purpose  of  concealment. 

S.  purpuratus.  The  common  purple  sea-urchin  of  the  west  coast, 
from  Sitka  to  Lower  California,  found  in  abundance  on  the  rocks  just 
beyond  low- water  marko  It  is  about  one  and  a  half  inches  in  diameter, 
with  rather  thick,  pointed,  and  fluted  spines. 

S,  franciscanus.  This  is  the  largest  species  of  the  west  coast,  the 
shell  measuring  sometimes  five  inches  across,  and  the  thick  spines  one  and 
a  haK  inches  in  length.  The  tubercles  on  the  naked  shells  are  very  promi- 
nent, and  the  zones  are  very  clearly  marked.  It  is  purple  in  color  and 
is  often  found  in  great  quantities  at  low- water  mark.  It  ranges  from 
Alaska  to  Lower  California.     (Plate  LVII.) 

Family  echinid^ 

In  this  family  the  ambulacral  plates  have  but  three  pairs  of 
pores. 


224  MARINE  INVERTEBRATES 

GrENUS  JEJchinus 

E,  gracilis.  This  is  a  deep-water  species,  which  occurs  from  Cape 
Cod  southward.  The  shell  is  nearly  spherical,  but  is  a  little  depressed 
on  the  oral  side,  and  has  twenty  bands  of  color,  alternately  green  and 
white.     The  spines  are  short  and  thin. 

Genus  Toxopneustes 

T,  variegatus.  This  is  the  common  species  of  the  Southern  States, 
from  North  Carolina  southward,  and  is  found  in  shallow  water  in  pro- 
tected places.  The  shell  is  nearly  globular ;  the  spines  vary  in  thickness 
and  color,  some  being  long,  slender,  and  greenish,  while  others  have 
stout  and  blunt  spines  of  a  yellowish  or  violet  tint. 

ORDER  CLYPEASTROIDEA 

CAKE-URCHINS 

The  animals  of  this  order,- commonly  known  as  sand-cakes  or 
sand-dollars,  are  flat  and  circular  like  disks.  Sometimes  they 
are  cut  at  intervals  on  the  margin ;  again  they  have  slits  through 
the  body  (hmales).  They  have  a  well-marked  star-shaped  figure 
on  the  dorsal  surface.  This  figure  is  formed  by  the  ambulacra, 
or  tube-feet,  which  run  in  five  rounded  or  petal-shaped  lines  on 
the  under  surface.  The  mouth,  in  Aristotle's  lantern,  is  in  the 
center  of  the  somewhat  concave  ventral  surface,  the  petal-like 
ambulacral  zones  meeting  at  the  central  space.  The  excretory 
opening  is  on  the  margin  of  the  disk,  at  a  point  between  two  of 
the  sections  of  the  star-like  figure.  This  marks  the  posterior  part 
of  the  body,  while  the  opposite  arm  of  the  star  marks  the  front 
or  anterior  end.  The  spines  are  very  fine  and  silky,  and  are 
spread  abundantly  over  the  whole  animal.  Clypeasteroids  are 
mainly  found  in  sand  considerably  below  low- water  mark,  though 
some  species  thrive  where  they  are  exposed  to  the  surf  on  open 
sandy  beaches. 

Family  ECHiNANTHiD.ffi 

Genus  Clypeaster 

C.  ravenelHL  This  species  occurs  in  deep  water  from  South  Caro- 
lina southward.  The  disk  is  about  four  inches  in  diameter,  and  is  raised 
in  the  center  into  a  large  cone.     The  ambulacra  run  down  the  sides  of 


CAKE-URCHINS 


225 


the  cone  in  straight  hnes,  and  around  the  base  is  a  depressed  area  which 
emphasizes  a  thick  border  which  extends  around  the  scalloped  margin. 
The  color  is  light  yellowish-brown.     (Plate  LVIII.) 


Genus  Echinanthiis 

E,  rosaceus.  This  is  a  large  species,  oblong  in  shape,  about  four  to 
five  inches  across  and  much  rounded  on  top,  the  body  being  about  two 
inches  thick.  The  ambulacral  zones 
are  depressed,  leaving  prominent 
elevations  which  make  a  very  con- 
spicuous figure  on  the  top .  The  color 
is  light  chocolate-brown.  Found 
close  to  the  shore  off  the  coasts  of 
Florida,  South  Carolina,  and  the 
West  Indies. 


Family  scutellid.^ 
Genus  Echinarachnitis 

THE   SAND-DOLLARS 

E,  lyarnia.  This  species,  the  shells 
of  which  are  very  common  obiects    ^ , .       ,  .  ^,         ,  ,  „       ,,    , 

T  T  ■,         •'/,  -v-  -r  Echtnarachnius  parma,  the  sana-dollar.    Much 

on  sand-beaches  trom  ISew  Jersey  smaller  than  natural  size. 

northward,  is  generally  known  as  the 

sand-dollar.  The  animals  have  flat  circular  disks  about  three  inches  in 
diameter.  The  ambulacral  zones,  in  five  petal-like  lines,  form  a  distinct 
figure  on  the  upper  sm-face.  The  mouth  is  in  the  center  of  the  ventral 
surface,  and  the  excretory  opening  is  on  the  edge  of  the  disk.  In  life 
they  are  covered  with  short,  fine,  silky  spines,  which  seem  like  hair,  and 
are  purplish-brown  in  color,  but  turn  green  when  taken  from  the  water. 
The  sand-dollars  are  exceedingly  abundant  off  Nantucket  Shoals,  where 
the  bottom  seems  paved  with  them.  They  are  eaten  in  great  numbers 
by  flounders,  cod,  and  haddock.  When  put  in  alcohol  they  stain  it  a 
dark  color.  Fishermen  prepare  an  indehble  ink  by  grinding  to  powder 
these  animals  and  mixing  it  with  some  hquid.  This  species  is  also  found 
on  the  northern  Pacific  coast. 

E.  excentricus.  This  is  the  common  sand- dollar  of  the  Pacific 
coast.  The  disk,  instead  of  being  circular  as  in  JE.  parma,  is  somewhat 
straight  across  the  posterior  end,  and  the  posterior  ambulacral  zones  are 
shorter  than  the  other  three.  The  upper  side  of  the  disk  is  raised,  form- 
ing a  cone -like  elevation,  the  apex  being  the  center  of  the  figure. 


Genus  Mellita 

M,  testudinata.  The  disk  is  rounded  in  front  and  straight  in  the 
back.  Four  long,  narrow  lunales,  or  cuts,  occur  on  the  sides  in  line 
with  the  ambulacral,  petal-shaped  zones,  but  do  not  extend  quite  to  the 
edge  of  the  disk }  and  a  wide  lunale  occurs  in  the  interambulacral  space 

15 


226  MARINE  INVERTEBRATES 

of  the  posterior  end.  The  three  anterior  zones  are  shorter  than  the  pos- 
terior pair.  On  the  upper  side  of  the  disk  the  spines  aU  turn  toward 
the  periphery.  The  color  of  the  hving  animal  is  greenish-blue.  It  is 
very  abundant  from  Cape  Hatteras  southward  in  shallow  water^  and  the 
shells  are  sometimes  found  as  far  north  as  Cape  Cod.     (Plate  LVIII.) 

Genus  JEncope 

E.  michelini,  Ambulacral  zones  unequal  in  size,  the  posterior  pair 
usually  longer  than  the  others ;  lunales  like  notches  in  the  margin,  with 
a  large  one  opening  between  the  posterior  ambulacral  zones  nearly 
in  the  center  of  the  disk ;  disk  rounded  in  front  and  square  at  the  back. 
Common  on  the  coasts  of  southern  Florida  and  the  Gulf  of  Mexico  in 
shallow  water.     (Plate  LVIII.) 


ORDER  SPATANGOIDEA 

HEART-URCHINS 

The  Spatangoidea,  or  heart-urchins,  have  heart-shaped  or  thick 
elliptical  bodies.  The  mouth  and  excretory  opening  are  both 
away  from  the  center  and  on  the  ventral  side.  These  animals 
seem  deformed,  so  much  are  they  out  of  symmetry  and  so  dif- 
ferent in  outline  from  the  other  orders  of  the  class.  The  am- 
bulacral zones  are  in  circles,  or  petaloid  in  outline,  as  in  cake- 
urchins,  but  are  not  continuous,  and  the  anterior  one  is  usually 
unlike  the  others  and  frequently  without  pores.  The  entire  body 
is  covered  with  spines,  and  these  are  the  chief  organs  of  locomo- 
tion ;  the  greater  part  of  them  turn  backward,  giving  the  living 
anijQal  the  semblance  of  a  porcupine.  The  mouth  is  protected  by 
a  projecting  plate,  but  Aristotle's  lantern  is  absent  in  this  order. 
The  anatomy  is  in  general  the  same  as  in  the  other  orders,  but 
the  organs  are  turned  in  conformity  with  the  inclosing  shell. 
Most  of  these  animals  bury  themselves  in  sand  or  mud  and  live  in 
deep  water ;  a  few  only  are  littoral  species. 

Family  spatangoid^ 

Genus  Moira 

M,  atropos.  Size  about  one  inch  by  one  and  a  half  inches,  and  one 
inch  thick  J  color  yellowish-white,  with  brown  spines.  Found  from 
North  Carolina  to  Florida,  from  the  shore  to  deep  water. 


PLATE  LVIII. 


Clypeaster  ravenellii. 
Encope  michelini. 
Lovenia  cordiforrais. 


Mellita  testudinata. 

Test  of  Metalia  pectoralis. 


HEART-URCHINS  227 

GrENUs  Lovenia 

L.  cordiformis.  About  one  inch  by  one  and  a  half  inches  thick ; 
reddish  in  color  -,  resembles  a  little  porcupine.  Found  on  the  southern 
California  coast.     (Plate  LVIH.) 

Genus  Sehi^aster 

S*  fragilis.  One  and  a  half  by  two  inches  in  size,  and  one  inch  thick ; 
color  brownish.    Lives  in  deep  water  off  the  eastern  coast. 

Genus  Metalia 

M,  pectoralis,  A  very  large  heart-urchin,  found  on  the  southern 
coast  of  Florida  and  in  the  West  Indies  in  shallow  water.  It  is,  per- 
haps, the  largest  species  found,  being  six  to  eight  inches  long  and  pro- 
portionately wide  and  thick.  The  shell  is  thin,  more  or  less  elliptical, 
and  densely  clothed  with  long  reddish-gray  spines.     (Plate  LVIH.) 

Genus  Brissopsis 

B.  lyrifera,  A  beautiful  deep-water  species,  found  off  the  coasts 
of  Florida  and  the  Gulf  of  Mexico.  It  has  a  red  body  with  pale- 
yellowish  spines.  In  size  it  is  about  two  by  two  and  a  half  inches,  and 
is  thickest  on  the  posterior  end.  It  is  thickly  clothed  with  long  curved 
spines,  some  of  which  form  two  long  tufts  in  the  back. 


TABLE  SHOWING  THE  CLASSIFICATION  OF  THE  HOLOTHUROIDEA 
DESCRIBED  IN  THIS  CHAPTER 


Orders 

ELASIPODA 

(Deep-sea    forms;     tube-feet    in 
zones  near  together) 

PEDATA 

(Well-developed  tube-feet  and  false 
ambulacra) 

AFODA 

C  Without  radial  canals,  tube-feet, 
or  respiratory  trees) 


Class 

HOLOTHUROIDEA 

Genera 


c  Thyone 
<  JPentacta 
(  Lophothuria 

(  Synapta 
i  Caudina 


Species 


T.  briareus 
P,  frondosa 
L,  fdbricii 

S.  tenuis 
S,  roseola 
S.  rotifera 
C,  arenata 


228 


CLASS  HOLOTHUROIDEA 

SEA-CUCUMBERS 

THE  holothurians,  or  sea-cucumbers,  althougli  in  appearance 
quite  unlike  starfishes  and  sea-urchins,  have  the  character- 
istic ambulacral  zones  and  other  features  of  the  group.  In  form 
they  are  cylindrical,  and,  when  the  tentacles  and  tube-feet  are 
retracted,  resemble  fat  worms;  when  fully  expanded  they  are 
somewhat  like  sea-anemones,  the  tentacles  forming  a  rosette-like 
top.  The  walls  of  the  body  are  tough  and  muscular,  with  small 
calcareous  deposits  or  spicules  of  various  shapes  in  the  skin. 
The  mouth  is  at  one  end,  the  excretory  opening  at  the  other,  and 
along  the  body  are  double  rows  of  tube-feet.  Often  instead  of 
tube-feet,  or  together  with  them,  are  conical  processes  without 
suckers.  The  ambulacra,  when  arranged  in  regular  zones,  are 
used  for  locomotion  only  in  the  lines  running  from  the  madre- 
poric  plate.  In  some  species  three  of  the  zones  are  near  together, 
and  form  a  kind  of  sole  on  which  the  animal  creeps ;  again  the 
tube-feet  are  wholly  suppressed,  as  in  Synapta.  Besides  progress- 
ing by  means  of  these  suckers,  the  holothurians  move,  as  do 
worms,  by  the  extension  and  contraction  of  the  body.  The  inner 
surface  of  the  tough  membrane  inclosing  the  body  is  lined  with 
powerful  longitudinal  and  transverse  muscles,  by  means  of  which 
the  creature  contracts  and  lengthens  its  body  and  changes  its 
form  in  a  wonderful  manner.  Around  the  mouth  are  tentacles, 
which  are  often  much  branched  and  are  uSed  as  organs  of  touch 
and  smeU,  and  sometimes  have  an  ear-sac  at  the  base.  From  the 
mouth  the  food-canal,  making  one  long  coil,  extends  to  a  chamber 
{cloaca)  at  the  other  pole.     The  cloaca  gives  off  a  pair  of  much- 

229 


230 


MARINE  INVERTEBRATES 


radamh 

rCr70V&S 

ri.blves 

pol.vee 
storrv- 
inived 


^enap 

raxji  OSS 
i?il&ross 


qen.du, 
mad.  can 
ird.ves 


^em.gri 


cvrcviuQ 


int 
int.ves 

int.ves 

lOTt^.TTlUd 


resfj 
c-irc.Tnus. 

lon^.TTUlB 


Zong.mus 


Internal  organs  of  a  Holothurian,  as  seen  when  the  body-wall  is  divided  along  the  middle  of 
the  dorsal  surface :  b.w.,  body-wall ;  circ.  mus.,  circular  layer  of  muscle ;  cl,  cloaca ;  cl.  op.,  cloacal 
opening  with  five  teeth  ;  cuv.  org.,  Cuvierian  organs ;  gen.  ap.,  genital  apertxire;  gen.  du.,  genital 
duct;  gen.  gl.,  genital  gland ;  "^Jii.,  intestine;  inter,  oss.,  interambulacral  ossicles;  int.  ws.,  in- 
testinal vessels;  long,  mus.,  longitudinal  band  of  muscle;  mad.  can.,  madreporic  canals;  mes., 
mesentery ;  pol.  ves.,  Polian  vesicles  ;  rad.  amb.,  radial  ambulacral  vessel ;  ri.  hi.  ves.,  ring  blood- 
vessel; resp.,  respiratory  trees;  rmgr-ves. ,  ring-vessel  of  the  ambulacral  system ;  siom.,  stomach. 


SEA-CUCUMBERS  231 

branched  respiratory  trees,  which  are  constantly  supplied  with 
water  by  the  contractions  of  the  cloaca.  At  the  base  of  one  of 
the  respiratory  trees  are  singular  structures  known  as  Cuvierian 
organs.  They  are  numerous,  viscid,  glandular  tubes,  which  the 
animal  can  throw  out,  and  which  will  adhere  closely  to  almost 
anything.  The  holothurian  has  a  water- vascular  system,  the 
madreporic  plate  being  near  the  mouth,  but  not  opening  to  the 
outside,  and  a  nervous  system  which  starts  from  a  ring  which 
lies  around  the  mouth.  The  egg-sacs  are  branched  tubes,  often 
highly  colored,  which  open  to  the  outside,  close  to  the  wreath 
of  tentacles  surrounding  the  mouth. 

The  larvae,  when  free-swimming,  are  called  Auricula.  In  the 
deep-water  species,  Cucumaria  crocea  and  Fsolus  epMpinger,  the 
eggs,  when  discharged,  and  the  young  are  carried  on  the  back  of 
the  mother.  In  Ciicuinaria  Icevigata  there  is  a  brood-pouch,  while 
in  Synapta  viviparia  the  young  develop  in  the  body-cavity. 

The  holothurian s  have  the  singular  power  of  ejecting  the 
whole  of  their  internal  organs  and  of  growing  them  again  in  case 
they  escape  the  enemy  they  have  endeavored  to  elude  by  this 
strange  method.  They  also  turn  themselves  inside  out,  as  it 
were,  as  if  from  nausea,  when  confined  in  water  too  stale  for  their 
uses.  Often  the  viscera  are  ejected  through  holes  in  the  sides  of 
the  body  broken  by  violent  muscular  contractions. 

Holothurians  are  generally  distributed  through  all  seas,  but  are 
congregated  in  greatest  numbers  in  Eastern  seas.  Their  habitat 
extends  from  shallow  to  very  deep  water.  They  are  found  in 
tide-pools,  on  rocks,  and  in  sand  or  mud.  Like  worms,  they  live 
on  organic  particles  contained  in  mud  and  sand,  which  they  take 
into  the  gullet  and  pass  through  the  alimentary  canal. 


ORDER  PEDATA     - 

Genus  Thyone 

T,  hriareus.  This  is  a  large  purple  holothurian,  found  in  shallow 
water  from  Texas  to  Cape  Cod.  It  is  four  to  five  inches  long  and  one 
inch  or  more  thick,  purple  in  color,  and  thickly  covered  over  its  whole 
surface  with  prominent  papillae. 


232 


MARINE  INVERTEBRATES 


Genus  Pentacta 

T,frondosa.  This  animal  is  commonly  caUed  tlie  sea-cucumber, 
and  the  popular  name  somewhat  expresses  its  form,  but  it  has  the  power 
of  changing  its  shape  in  a  most  surprising  manner.     Sometimes  it  will 

be  nearly  globular,  again  long  and  thin, 
or  it  may  be  constricted  like  an  hour- 
glass. When  at  rest  the  body  is  ovate 
and  somewhat  pentagonal.  On  the  an- 
gles are  double  lines  of  suckers,  and 
in  the  interambulacral  zones  are  a  few 
scattered  false  ambulacra.  The  surface 
is  nearly  smooth,  very  dark  purple  on 
one  side,  and  inclined  to  whitish  on  the 
other.  Ten  much-branched  tentacles 
surround  the  mouth.  The  animal,  when 
grown  and  expanded,  measures  fifteen 
to  eighteen  inches  in  length.  This 
species  is  found  throughout  the  whole 
length  of  both  the  east  and  the  west 
coasts.  It  is  very  plentiful  on  the  Maine 
coast  in  tide-pools  and  on  the  rocks  at 
low-water  mark.      The   genus  ranges 


Pentacta  frondosa,  the  sea-cucumber. 


over  the    greater  part  of  the 
globe.      The    tough    muscular 
body  is  said  to  be  edible,  tasting 
somewhat  like  lobster,  or  tre- 
pang  {Holothuria  eduUs),  which 
is  found  on  coral  reefs  in  East- 
ern seas  and  is  much  valued  as 
food  by  the  Chinese.     The  internal  organs 
of  P.  frondosa  are  highly  colored,  making 
its  anatomy  easy  to  trace.     The  muscular 
system  is  plainly  defined. 

Genus  Lophothuria 

L.fabricii  (Verrill),  Psolus  fabricii 
(Diiben),    Cuvieria  sqiiamata   (D.  and 

K.  :Agassiz).  The  body  in  this  species 
is  covered  with  rounded  overlapping  scales 
and  numerous  granulations,  and  when  it 
is  retracted  is  about  two  and  a  half  to  three 
inches  long  and  about  one  inch  thick. 


Lophothuria  fabricii,  showing  under  sur- 
face with  three  rows  of  ambulacra. 


SEA-CUCUMBERS  233 

rows  of  tube-feet  lie  near  together,  on  a  flat  under  surface,  and  form  a 
kind  of  sole  on  which  the  animal  creeps.  The  oral  end  of  the  body  is  a 
little  raised  and  bears  ten  tentacles ',  these  tentacles  are  profusely  and 
finely  branched,  and  when  expanded  are  about  as  long  as  the  body. 
The  aboral  end  is  obtuse  and  a  little  raised.  Around  the  oral  and  anal 
openings  the  scales  are  grouped,  forming  circles  in  those  regions.  This 
holothurian  is  bright  red  in  color,  and  when  expanded  is  a  beautiful 
object,  perhaps  the  most  attractive  in  appearance  of  any  in  the  class. 
When  retracted  it  has  the  aspect  of  an  ascidian,  and  for  a  time  was 
supposed  to  belong  to  that  group.  It  is  found  on  the  New  England  coast 
on  the  under  side  of  large  shelving  rocks. 

ORDER  APODA 

GrENUs  Synapta 

S,  tenuis.  This  curious  animal  is  long  and  slender,  and  so  transpa- 
rent that  its  internal  organs  are  clearly  visible.  Around  the  mouth  are  a 
circular  tube  and  a  wreath  of  twelve  branching  tentacles.  There  are  no 
ambulacra.  Little  spots  scattered  irregularly  over  the  surface  show, 
when  highly  magnified,  small  warts,  each  one  of  which  has  a  calcareous 
projection  shaped  like  a  little  anchor.  By  means  of  these  anchors  and 
by  the  contractions  of  its  body  the  animal  moves  through  the  mud  or 
sand  in  which  it  lives,  near  low-water  mark.  The  sand  is  collected  into 
rings  at  the  oral  end  and  pushed  downward  until  the  whole  animal  is 
inclosed  in  a  sand-tube.  When  empty  Synaptais  white  and  transparent, 
and  the  digestive  canal  may  be  seen  wound  in  a  spiral  throughout  its 
length ;  but  when  gorged  with  food,  sand,  pebbles,  and  shells  can  be 
distinctly  seen  filling  the  food-canal,  and  the  body  then  has  a  dark- 
gray  color.  Synapta  grows  to  a  length  of  eighteen  inches  or  more,  but 
is  constantly  breaking  pieces  off  its  posterior  end  by  muscular  contrac- 
tions. When  kept  in  confinement  it  soon  commences  to  constrict  its 
body  at  various  points,  and  after  a  few  hours  there  is  nothing  left  but  a 
mass  of  fragments.  It  is  viviparous,  that  is,  it  carries  its  young  in  the 
body-cavity ;  the  eggs  are  hatched,  and  the  young  approach  maturity 
before  they  are  expelled.  This  species  ranges  from  Cape  Cod  to  North 
Carolina,  and  can  be  found  in  the  upper  part  of  its  burrows  when  the 
tide  is  out. 

S,  roseola.  This  species  occurs  in  the  same  localities  as  S.  tenuis,  and 
differs  from  it  mainly  in  color,  which  is  pale  red,  due  to  minute  red  spots 
scattered  through  the  skin. 

S,  rotifera,  A  species  found  in  Florida.  It  is  light  purplish  in  color, 
and  has  eight  or  ten  branches  on  each  of  the  twelve  tentacles.  In  this 
species  the  spicules  of  lime  in  the  skin  are  shaped  like  wheels  iu  stead  of 
anchors. 

GrENus  Caudina 

C.  arenata.  About  four  inches  long  and  tapers  to  the  ends ;  the 
posterior  end  sometimes  narrowed  to  a  long,  slender,  tail-like  extremity ; 
tentacles  around  the  mouth  resemble  cloves.  It  lives  in  sand  and  may 
be  found  on  the  New  England  coast,  washed  ashore  after  a  storm. 


234 


MARINE  INVERTEBRATES 


Class 
CRINOIDEA 

Genera 

JPentacrinus 

Comatula 


CLASS  CRINOIDEA 

FEATHER-STARS   AND   SEA-LILIES 

The  crinoids  are  inhabitants  of  deep  water,  where  they  grow 
in  great  numbers,  forming  beds  of  sea-lilies.  Their  general 
form,  which  suggests  the  lily,  and  their  feather-like  manner  of 
branching,  give  them  the  two  common  names  of  sea-lilies  and 
sea-feathers.  They  have  a  long,  jointed  stalk,  one  end  of  which 
is  attached,  while  the  other  bears  the  disk  of  the  animal.  From 
the  disk  emanate  five  arms,  which  divide  near  the  base,  making 


^^fri\^^ 


The  feather-star  (AntedonJ,  illustrating  the  Comatula  form  of  crinoid. 


CRINOIDS 


235 


ten  arms  in  all.  The  arms  have  short  branches  along  the  sides. 
Ambulacral  grooves  follow  the  center  of  all  the  arms  and 
branches.  The  mouth  is  in  the 
center  of  the  npper  side,  which 
in  this  case  is  the  ventral  surface. 
The  genus  Pentacrinus  remains 
permanently  attached,  but  Co- 
matula,  at  a  certain  stage  of  de- 
velopment, separates  from  the 
stalk  and  swims  freely  about  by 
means  of  its  arms.  It  can  attach 
itself  temporarily  by  tubular  pro- 
cesses, which  are  developed  on  the 
dorsal  surface  at  the  point  where 
the  stem  was  attached.  The  ossi- 
cles, or  plates  which  cover  the 
dorsal  surface,  are  free,  making 
the  crinoid  an'  animal  of  innu- 
merable joints. 

The  crinoids  are  particularly 
interesting  from  the  fact  that  they 
have  existed  from  early  geologic 
times,  and  their  history  is  written 
in  stone.  In  the  early  ages  they 
were  the  only  class  of  echino- 
derms,  and  their  evolution  into 
other  forms  can  be  traced  through 
successive  geologic  periods.  They 
existed  in  such  vast  numbers  that 
the  fossil  forms  are  plentiful  and 
are  familiar  to  every  student  of 
geology,  and  are  known  as  stone- 
lilies  and  encrinites.  To-day  they 
are  decadent,  there  now  remaining 
only  twelve  of  the  two  hundred  genera  which  existed  formerly.  A  fine 
bed  of  crinoids  is  found  off  Cuba,  on  the  slope  of  the  coast  where  the 
water  rapidly  deepens  from  one  hundred  to  two  hundred  fathoms. 


Pentacrinv.s  aster ia. 


236  MAEINE  INVERTEBRATES 

Although  the  crinoids  are  deep-water  forms^  and  are  never 
found  on  the  beach,  they  are  given  here  because  they  follow  in 
the  system  of  classification  and  illustrate  another  curious  class  of 
echinoderms.  The  brief  description  given  may  add  interest  to  the 
fossil  forms  to  be  seen  in  museums. 


VI 

ARTHROPODA 


TABLE    SHOWING    THE    CLASSIFICATION    OF    THE    ABTHROPODS 
DESCRIBED    IN    THIS    CHAPTER 

Phylum 

ARTHROFODA 

Class 
CRUSTACEA 

Subclass 
Entomostraca 

(Crustacea  of  small,  often  of  almost  m,icroscopic  minuteness,  and  of  comparatively 
simple  organization;  appendages  have  little  differentiation) 

Order  PHYLLOPODA 
(Appendages  resemble  leaves,-   mostly  fresh-water  species) 


Suborders 

EUPHYLLOPODA 

(Phyllopoda  of  considerable 
size,  bearing  ten  to  sixty 
pairs  of  leaf-like  swim- 
ming-feet) 

CLADOCERA 

(Small  phyllopoda ;  body 
laterally  compressed ;  cara- 
pace like  a  bivalve  shell; 
four  to  five  pairs  of  swim- 
ming-feet; chief  organs  of 
locomotion  are  the  bira- 
mous  antennce ;  abdomen 
devoid  of  appendages.  They 
abound  in  fresh  water,  are 
very  prolific,  and  afford  a 
large  amount  of  food  to 
fresh-water  fishes) 


Genera 


Daphnia 
Leptodora 
Moina 
Polyphemus 


Order  OSTRACODA 


(Resemble  minute  bivalve  shells ;  swim  by  anteniice ;  body  unsegmented ; 
appendages  seven  pairs  only) 

Cypris  (fresb-water) 
Cypridina  (marine) 
238 


ARTHROPODA 


239 


Order  COPEPODA 

(Small  size;  body  long,  segmented;  four  to  five  pairs  of  once-branched  appendages  on 

thorax;  abdomen  without  appendages;  abundant  in  fresh  and 

salt  water;  many  forms  parasitic) 

Genera 

Cyclops 

Cetochilus  , 

SapphiHna 

Siphonostomata 

NicotJioe 


Order  CIRRIPEDIA 

(Im,perfectly  segmented;  fixed  or  parasitic  during  adult  life;  inclosed  in  sTcin 

strengthened  by  calcareous  plates;   abdomeii  rudimentary; 

appendages  biramous,  usually  six  pairs) 


Suborders 


RHIZOCEPHALA 

(Parasitic) 


Genera 


Species 

L,  anatifera 
L,  striata 
L,  pectinata 
B.  halanoides 
B,  ehurneus 
IB,  rugosus 
B,  geniculatus 
B,  tintinnabultim 
Sacculina  (parasitic  on  crabs) 
JPeltogaster  (parasitic  on  hermit-crabs) 


Lepas 


Balanus 


Subclass 
Malacostraca 

(Sighly  organized  Crustacea,  usually  of  considerable  size;  appendages  much  differentiated) 

Order  PHYLLOCAEIDA 

(Small;  covered  with  bivalved  carapace;  thoracic  feet  leaf -like;  abdominal  feet 

biramous;  posterior  segment  terminates  in  two  long  spines; 

mostly  fresh-water  species) 

Order  SCHIZOPODA 

(Small;  transparent;  shrimp-like;  thorax  inore  or  less  completely  covered  with  soft 
carapace;  thoracic  appendages  biramous;  eyes  on  stalks) 

Mysis  M,  sternolepis 

(Without  gills  or  thoracic  legs) 

Euphausia 

(With  gills  or  thoracic  legs) 


240 


MARINE  INVERTEBRATES 


Older  DECAPODA 

(Thoracic  segments  unite  with  head  and  form  cepJialothorax,  ivhich  is  covered  by 

carapace;  eyes  stalked ,-  maxillipeds  have  exopodites ;  five  pairs 

of  walking-feet  without  exopodites) 

Suborders 

MACRURA 

(Abdomen  usually  longer 
than  cephalothorax  and 
cotnmonly  extended ;  ros- 
trum usually  protninent; 
eyes  not  inclosed  in  orbits ; 
antennae  and  antennules 
large;  antennae  have  exo- 
podites) 


Genera 


1  Penceus 


Free-swimming  Forms : 
Shrimps  and  Prawns 


Palcem  onetes 
Crangon 

Creeping  Forms:  (HomaruS 

Lobsters  and  Crawfish    jig^^ijjgg      I 

ASTACOID^  I  I*<x,nulirus 
^Scyllarus 

Anomalous  Forms: 
Approaching  the  Brachyura 

ANOMURA 

BROMIDE    Hippoconcha 


JPagurus 

PAGURID^^f 

I  Clibanarius 
V  JPylopagurus 

CENOBiTiD^     Cenobita 


HIPPID^ 


PORCELLANID^ 


Hippa 

i  Alhuncea 
i  JPorcellana 

)  Petrolisthes 
(lAthodes 


iEchidnocerus 
AcanthoUthodes 
Cryptolithodes 
Fhyllolithodes 


Species 

K  P,  setiferus 
(  JP,  hrasiUensis 

JP,  vulgaris 
J  C  vulgaris 
(  C.  franciscoruni 

H.  americanus 
^  P.  interruptus 
\  JP.  argus 


H,  arcuata 
P,  bernhardus 
,  P.  pollicaris 
P.  longicarpus 
C,  vittatus 

C.  diogenes 
H,  talpoida 
H.  analoga 
A,  gibbesii 
P.  sayana 
\  P.  sexspinosus 
P,  armatus 
L,  maia 
E,  cibarius 
E,  foriminatus 
A,  hispidus 
C  sitchensis 
P,  papillosus 


ARTHROPODA 


241 


Suborders 

BRACHYURA 

(Abdomen  shorter  than 
cephalothorax,  mid  perma- 
nently folded  ^lnder  it;  eyes 
inclosed  in  orbits,-  anten- 
nules  and  antennce  small) 


Families  Genera 

i  Carcinides 

PORTUNiD^.    -)  Cauinectes 

(Swimming  crabs)  i  ^^       -,. 

^  C  Ovalipes 


Cancer 


1— I 

M 


CANCROIDS 

Menippe 
Eupanopeus 
Eurypan  opens 
Neopaji  opens 
HhitJiropanopeus 

GRAPSiD^  S  Heniigrapsus 


OCYPODID^ 

(Sand-  and  fiddler-ct 


(  Pacygrapsiis 
r  Ocypoda 


•abs)^ 


TJca 


MAIID^ 

(Spider-crabs) 


CALAPPID^ 
PINNOTHERnD^ 


Libinia 

Hyas 

Loxorhynchus 
Piigettia 
Sternorhynchus 
Epialtiis 
Pitho 
\Lanibrus 
Calappa 
Pinnotheres 


Species 

C  mcenas 
C  sajndus 
O.  ocellatus 

'  C,  irroratus 
C,  horealis 
C,  inagister 
C  prodiictus 

,0.  antennarius 
M,  mercenaria 
E,  herbstii 
E,  depresstis 
N,  texana 
It,  liarrisii 

\  H,  nndns 
H.  oregonensis 
J*,  crassijyes 
O.  arenaria 
U.  minax 

I  U.pugnax 

.  U,  2J^iffil((for 

\  L,  dubia 

'  L,  emarginata 
H,  coarctatus 
H^  lyratus 
JET.  araneiis 
L,  crispatus 
P,  gracilis 
S,  Sagittarius 
E,  productus 
P,  acideata 
li.  poiiHalesii 
C.  flamma 
P,  ostreum 


Order  STOMATOPODA 
(Abdomen  very  large,-  second  pair  of  thoracic  legs  very  large,-  gills  borne 


16 


on  abdominal  segments) 

Squilla 


S,  einpusa 


242 


MARINE  INVERTEBRATES 


Suborders 


Order  CUMACEA 
(Small,  shrimp-like) 

Genera 
I>iastylis 

Order  ARTHROSTRACA 


Species 
D,  quadrispinosus 


(No  carapace,  as  a  rule,-  six  to  seven  pairs  of  walking-legs ;  eyes  sessile) 


AMPHIPODA 

(Body  usually    compressed 
laterally) 


ISOPODA 

(Body  depressed  or  flattened) 


Oi^chestia 

Talorchestia 

Gammariis 

CJielura 

Caprella 

Cirolana 

Lininoria 

Sphceroma 

Idotea 


Chiridotea 

Class 
MERISTOMES 

Order  XTPHOSURA 
lAmuliis 

Class 
PANTOPODA  (Lang) 

Order  PYCNOGONIDA 
Phoxichilidiuin 


0.  agilis 

T»  longicornis 
6r.  lociista 
C  terebrans 
C.  geometrica 

C.  concharum 

Zi,  lignorum 

S,  quadridentatiim 

1,  marina 
I.  ochotensis 
I,  metallica 

I,  wosnesenshii 

C,  ccBca 
C  entomon 


X.  polyphemus 


P.  tnaxillare 


TERI^IS  USED  IN  DESCRIBING  CRUSTACEA 

Abdomen:  The  posterior  part  of  the  body. 

Antennce:  Articulated  appendages  which  immediately  precede 
the  mouth. 

Anten'nules :  The  anterior  of  the  two  pairs  of  feelers  of  the  head. 

Bira'moiis :  Having  two  branches. 

Carapace :  A  thin  chitinous  shell  covering  the  cephalothorax. 

Cephalic:  Pertaining  to  the  head. 

Cephalotho'rax :  The  united  head  and  thorax. 

Chela:  The  pair  of  pincers,  or  claw,  which  terminates  some  of 
the  appendages. 

Che'liped:  A  leg  with  chela,  or  claw,  at  the  end. 

Endop'odite :  The  inner  one  of  the  two  main  divisions  of  the 
limb. 

Epinie'ra:  Divisions  on  the  ends  of  the  segments  of  amphi- 
pods  and  isopods,  and  belonging  to  the  legs. 

Epip'odite :  A  third  branch  of  a  limb. 

Epis'toTina :  A  triangular  area  in  front  of  the  mouth. 

Exojyodite:  The  outer  one  of  the  two  main  branches  into 
which  the  tj-^ical  limb  of  any  segment  is  di"vdded. 

Gastric  mill :  The  first  half  of  the  stomach,  where  food  is  ground. 

Mandibles :  The  pair  of  appendages  next  behind  the  antenna. 

Maxirice:  The  first  pair  of  appendages  after  the  mandibles. 

Maxillipeds :  The  three  pairs  of  appendages  after  the  maxillae. 

Metame'res :  Segments. 

Orbits :  Eye-cavities,  peculiar  to  the  higher  Crustacea. 

JProsto'mium :  The  region  in  front  of  the  mouth ;  the  preoral 
part  of  the  head. 

nostrum:  The  beak  in  front  of  the  head. 

Segment :  A  part  cut  off  or  marked  as  separate  from  others. 

Som^ite :  A  segment  of  the  body. 

Squame :  A  scale. 

Telson :  The  last  segment  of  the  abdomen. 

Thorax :  The  middle  part  of  the  body. 

243 


ARTHEOPODA 

THIS  subdivision  of  the  animal  kingdom  includes  insects,  cen- 
tipedes, spiders,  and  crustaceans,  whicli  together  constitute 
more  than  half  the  known  species  of  animals.  Although  these 
animals  are  so  unlike  in  general  appearance,  it  is  easy  to  recog- 
nize the  common  characteristics  which  place  them  together  in 
one  group.  The  name  Arthropoda,  meaning  '' jointed-footed," 
suggests  perhaps  one  of  the  most  obvious  points  of  resem- 
blance. The  Arthropoda  have  bilateral  symmetry,  one  side  of 
the  body  being  like  the  other  5  they  are  covered  with  a  horn-like 
material  (chitin) ;  they  are  divided  into  segments ;  the  segments 
have  appendages ;  and  the  appendages  are  jointed  so  as  to  admit 
freedom  of  motion.  Their  manner  of  growth  is  peculiar ;  they 
cast  off  their  rigid  external  coverings  and  secrete  larger  coats  of 
mail,  and  at  these  periods  increase  in  size  or  undergo  meta- 
morphosis. 

There  are  such  modifications  of  these  general  features  as  the 
habits  of  the  different  species  demand.  For  instance,  the  appen- 
dages may  be  constructed  for  walking,  swimming,  boring,  sucking, 
or  the  seizure  and  preparation  of  food.  In  some  animals  the 
appendages  form  a  part  of  the  breathing-organs,  in  others  are 
used  as  organs  of  sense.  Every  detail  of  the  organism,  down  to 
the  hairs,  has  its  special  use  and  function. 

CLASS  CRUSTACEA 

The  crustaceans  vary  in  size  from  microscopic  minuteness  to 
two  feet  or  more  in  length.  The  giant  crab  of  Japan  {Kaempferia 
Jcaempferi)  exceeds  this,  being  commonly  from  eight  to  twelve  feet 

244 


CRUSTACEANS  245 

across  the  arms,  and  is  said  to  reach  even  greater  proportions. 
Crustaceans  live  on  land  and  sea,  and  in  both  fresh  and  salt  water ; 
they  may  be  parasitic,  sedentary,  or  free  and  active.  There  are 
said  to  be  over  ten  thousand  species,  which  include  crabs,  lobsters, 
shrimps,  beach-fleas,  wood-lice,  barnacles,  and  water-fleas.  Nine 
tenths  of  the  species  are  marine;  of  these  some  are  pelagic, 
and  their  transparent  forms  constitute  a  part  of  the  plankton. 
Others  live  on  the  bottom  in  deep  water  and  attain  a  large  size, 
A  vast  number  live  in  the  littoral  zone  and  form  a  considerable 
part  of  that  crowded  community.  They  are  scavengers  and  free- 
booters, being  great  fighters,  as  well  as  predatory  in  their  habits. 
As  a  rule,  they  feed  on  dead  organic  matter,  which  they  consume 
in  surprising  quantities ;  some  have  also  a  vegetarian  diet.  They 
have,  like  starfishes,  the  singular  power  of  throwing  off  their 
limbs  and  growing  new  ones. 

The  Crustacea  derive  their  name  from  the  nature  of  their  crust 
or  covering.  This  is  earthy  and  brittle,  not  stony,  like  the  shells 
of  mollnsks.  This  crust,  or  exoskeleton,  has  various  degrees  of 
firmness,  from  that  of  a  delicate  polished  cuticle,  seen  in  small 
forms,  to  the  heavy  armor  of  some  crabs  and  the  shell-like  char- 
acter of  the  covering  of  barnacles. 

The  lobster  and  crab  are  perhaps  the  most  comprehensive 
examples  as  well  as  the  largest  in  size  of  the  class,  the  vast 
majority  of  the  species  being  minute  forms.  The  ocean  swarms 
with  varieties  too  small  to  be  noticeable  to  the  naked  eye. 

It  is  the  province  of  Crustacea  to  consume  decaying  organic 
matter,  both  animal  and  vegetable,  and  in  doing  this  they  per- 
form a  great  service  in  purifying  the  waters  of  the  poolj  the  shore, 
and  even  the  sea.  Not  only  in  this  are  they  serviceable,  but  to  a 
great  extent  they  serve  as  food  for  other  animals,  their  flesh  being 
palatable  and  preferred  to  that  of  other  animals  whose  diet  would 
seem  to  make  them  more  wholesome.  The  small  forms  exist  in 
such  myriads,  and  increase  so  rapidly,  that,  although  extremely 
small,  they  furnish  an  inexhaustible  supply  of  food.  Even  some 
whales  subsist  upon  these  minute  animals,  and  for  man  the  larger 
species  are  articles  of  diet  that  are  counted  among  the  luxuries. 
The  crustaceans  are  remarkable  for  their  varied  forms  and  for  their 


246  MARINE  INVERTEBRATES 

perfect  adaptation  to  many  different  conditions  of  life.  There  is 
no  class  in  the  animal  kingdom  which  presents  so  wide  a  range 
of  organization,  or  whose  structure  deviates  so  widely  from  the 
type  form.  These  differences  lie  chiefly  in  the  external  charac- 
ters and  in  the  structure  of  the  appendages. 

Some  species  are  solitary,  like  lobsters  and  crabs ;  others,  like 
shrimps,  are  gregarious  and  live  in  immense  shoals.  In  the 
habits  of  these  animals  there  is  much  which  excites  wonder  and 
interest. 

ANATOMY   OF   THE   HIGHER   CRUSTACEA 

The  body  of  a  crustacean  is  divided  into  segments,  which  are 
sometimes  distinctly  separated,  like  joints,  and  sometimes  fused 
into  one  piece.  The  head  part  is  called  the  cephalic  portion,  the 
middle  section  is  the  thorax^  and  the  posterior  part  is  the  abdomen. 
The  horn-like  covering  of  the  thorax  is  the  carapace;  where  it 
projects  over  the  head  it  is  the  rostrum.  When  the  head  and 
thorax  are  united,  as  in  most  Crustacea,  the  anterior  or  front  por- 
tion of  the  animal  is  called  the  cephalothorax.  Each  segment  has 
a  pair  of  appendages.  Each  appendage  has  a  joint  attached  to 
the  body  5  from  this  arise  two  jointed  branches,  the  endopodite 
and  the  exopodite,  the  inner  and  the  outer  foot.  The  appendages 
are  modified  to  perform  special  functions.  In  front  of  the  mouth 
are  two  pairs :  the  smaller  ones  are  the  antennules  and  have  ears 
at  the  base ;  the  larger  ones  are  antennae  and  are  feelers.  At  the 
base  of  the  antennae  are  the  green  glands,  said  to  have  renal  func- 
tions. Both  the  antennules  and  the  antennae  are  fringed  with 
hairs,  which  aid  in  the  sense  of  touch  and  perhaps  of  smell.  On 
each  side  of  the  mouth  are  the  mandibles.  Then  come  the  max- 
nice  and  the  maxillipeds,  used  in  capturing  and  tearing  the  food 
and  conveying  it  to  the  mouth.  Thus  it  will  be  seen  that  some  of 
the  appendages  around  the  head  are  connected  with  the  senses,  and 
others  are  used  in  eating.  Those  of  the  thorax  are  for  walking ; 
those  of  the  abdomen  for  swimming,  guarding  the  eggs,  etc.  The 
food  taken  into  the  mouth  passes  into  the  stomach  through  a 
short  passage.     The  stomach  is  divided  into  two  parts.     The  front 


CRUSTACEANS  247 

one  contains  three  long  teeth  which  meet  laterally  and  grind  the 
food ;  this  is  known  as  the  gastric  mill. 

When  sufficiently  fine,  the  food  passes  through  a  strainer  of 
stiff  bristles  into  the  smaller  portion  of  the  stomach,  where  it  is 
partially  digested,  and  from  there  enters  a  long,  straight  intes- 
tine which  reaches  the  length  of  the  body  and  opens  to  the  out- 
side on  the  under  side  of  the  telson,  or  last  segment.  A  large 
liver  also  pours  its  secretions  into  the  intestine.  The  green  sub- 
stance commonly  called  "  fat ''  in  lobsters  is  the  liver. 

The  heart  consists  of  an  elongated  tube,  or  a  short  sac,  which 
lies  directly  under  the  integument  of  the  back.  From  this  heart- 
sac,  blood,  which  is  colorless,  is  sent  by  arteries  to  all  parts  of  the 
body ;  it  then  collects  in  spaces  called  venous  sinuses,  from  which 
it  goes  to  the  gills,  and  thence  back  to  the  heart. 

The  nervous  system  begins  in  a  large  ganglion  in  front  of  the 
mouth,  called  the  brain  ;  from  this  two  branches  arise,  which  pass  on 
each  side  of  the  digestive  organs,  meeting  in  ganglia  in  each  seg- 
ment and  extending  the  w^hole  length  of  the  body.  The  gills,  by 
which  the  animal  breathes,  are  upon  the  limbs,  or  on  the  walls  of 
the  body  immediately  adjacent  to  them,  and  are  generally  inclosed 
in  special  chambers.  In  lobsters  and  crabs  two  such  chambers 
are  found  under  the  flaps  of  the  carapace,  above  the  walking-legs. 
Gills  are  divided  so  as  to  present  much  surface  to  the  water,  from 
which  they  absorb  oxygen.  They  are  like  a  dense  mass  of  little 
tubes  arranged  along  a  central  tube.  The  class  has  two  kinds  of 
eyes,  simple  and  compound ;  the  latter  are  composed  of  a  number  of 
eyes.  In  some  species  the  eyes  are  placed  on  the  ends  of  mova- 
ble stalks,  which  enable  the  creature  to  see  in  all  directions  and 
from  a  higher  plane  than  the  body  occupies.  As  a  rule,  the  eyes 
occur  in  the  head  region,  but  in  the  shrimp  Uiiphausia  they  are  on 
the  thorax  and  abdomen.  In  barnacles  simple  eyes  exist  in  the 
young  stage,  but  in  adult  forms  there  are  no  apparent  visual  organs. 
The  ear  (so  called)  consists  of  a  sac  containing  small  silicious 
particles  suspended  in  fluid.  Numerous  fine  hairs  on  the  inner 
surface  of  the  sac  connect  with  nerve-fibrils. 

The  organs  of  hearing  are  in  various  places.  In  decapods,  or 
the  larger  Crustacea,  they  are  at  the  base  of  the  antennules. 


248 


MARINE  INVERTEBRATES 


Zoea  of  Cancer  irroratus.  Last  stage 
before  it  changes  to  the  megalops  con- 
dition. 


The  muscles  are  white  bundles  of  fibers,  and  are  in  strips, 
which  is  an  indication  of  power  and  activity.  There  are  four 
important  sets :  twisted  ventral  muscles  which  bend  the  tail  and 
are  particularly  large  and  strong,  those  which  straighten  the  tail, 

those    moving   the    appendages,   and 
those  which  work  the  gastric  mill. 

The  eggs,  after  being  discharged, 
are  attached  to  the  abdominal  legs  of 
the  mother  by  a  kind  of  cement,  or 
they  are  carried  in  pouches  attached 
to  the  thorax.  In  these  positions  they 
mature,  and  hatch  at  different  stages 
of  development  in  different  species. 
Some  emerge  with  three  pairs  of  legs, 
and  are  known  as  NaupUiis;  some  are 
Zoea,  having  a  carapace  and  abdominal 
segments,  but  no  abdominal  ap23endages.  Another  stage  is  Megalops, 
with  large  stalked  eyes.  Others  are  hatched  as  miniature  adults. 
These  names  were  given  when  the  embryo  stage  was  not  recog- 
nized aud  the  larvae  were  thought  to  be  distinct  species. 

The  growth  of  the  animal  is  effected  by  moulting.  The  Crus- 
tacea are  named  from  the  crust-like  covering 
which  envelops  them.  It  is  a  horny  material, 
called  chitin,  in  which  are  deposited  particles 
of  carbonate  of  lime,  making  a  rigid  envelop 
which  would  prevent  all  freedom  of  motion, 
were  it  not  that  there  are  spaces  free  from 
lime,  and  thus  flexible  joints  are  left.  When 
the  animal  expands  it  throws  off  this  hard 
covering  and  secretes  a  new  and  larger  one. 
As  the  time  of  moulting  approaches,  the  old 
covering  becomes  loosened,  and  a  delicate 
new  one  is  formed  beneath  it.  The  old  shell 
splits  open  across  the  back  just  behind  the 
carapace,  and  the  soft  animal  withdraws  first  its  cephalothorax 
and  then  its  abdomen,  leaving  the  cover  complete,  including  even 
the  covering  of  the  eyes  and  the  lining  of  the  stomach.     The 


Megalops  stage  of  Cancer 
irroratus,  just  after  change 
from  zoea  stage. 


CRUSTACEANS  249 

new  shell  is  rapidly  hardened,  being  already  formed  when  the  old 
one  is  cast,  and  the  animal  regains  its  normal  condition  in  about 
a  week ;  in  the  meantime  it  is  defenseless,  and  lies  quiet  in  some 
secluded  place.  Moulting  is  an  exhausting  process,  and  is  attended 
with  great  dangers.  A  great  mortality  occurs  at  this  time  from  ac- 
cidents, from  weakness,  and  also  from  helplessness  in  case  of  attack. 
The  hair-like  processes  scattered  over  the  shell,  often  like 
fringes,  are  said  to  be  organs  of  feeling. 

SUBCLASS    ENTOMOSTRACA 

These  are  Crustacea  of  small,  often  microscopic  size,  of  com- 
paratively simple  organization,  and  with  appendages  adapted 
to  serve  the  purpose  of  respii'ation.  These  minute  animals 
may  be  obtained  by  skimming  the  surface  of  the  water  with 
a  muslin  net,  preferably  at  night,  then  washing  off  the  inside  of 
the  net  with  a  small  quantity  of  water  into  a  glass  dish.  Place  the 
dish  on  a  dark  surface  before  a  light,  and  the  little  creatures  will 
gather  toward  the  light,  and  may  be  satisfactorily  observed  with 
a  glass. 

ORDER  COPEPODA 

This  order,  though  composed  of  minute  forms,  is  one  of  great 
economic  importance,  from  the  fact  that  the  little  crustaceans  exist 
in  vast  numbers  and  furnish  a  very  considerable  part  of  the  food 
of  many  fishes.  Cyclops  is  the  most  common  of  the  fresh- 
water, and  Cetochiliis  of  the  marine  genera.  These,  together  with 
other  genera,  swarm  in  water  wherever  life  exists,  from  the  smallest 
pools  and  ditches  to  the  broad  surface  of  the  ocean.  Without  hav- 
ing drawn  a  surface-net  on  some  sheltered  bay,  it  is  difficult  to  have 
an  idea  of  the  myriads  of  Entomostraca  in  the  sea.  Although 
nearly  transparent  and  of  such  delicate  texture  as  to  be  almost 
jelly-like,  they  sometimes  color  the  sea  with  a  reddish  tint  for 
miles.  Whales  which  have  baleen,  or  fringes  of  whalebone, 
in  the  mouth  subsist  on  these  small  organisms,  which  are 
called  "  brit "  by  the  whalemen.  The  whales,  sometimes  in  schools, 
rush  through  the  water  with  open  mouths,  engulfing  these  little 


250  MARINE  INVERTEBRATES 

crustaceans,  the  baleen  straining  them  from  the  water.  Although 
devoured  in  such  immense  quantities,  and  sometimes  lying  dead  in 
sheets  of  scum  on  the  surface  of  the  water,  they  maintain  their 
numbers  by  the  exceeding  rapidity  with  which  they  reproduce. 
It  has  been  computed  that  the  descendants  of  one  Cyclops  may 
number  in  one  year  4,500,000,000,  provided  all  the  young  reach 
maturity  and  produce  a  full  number  of  offspring. 

One  of  the  free  marine  forms,  Sa^fphirina,  is  of  especial  inter- 
est, as  it  surpasses  all  animals  in  phosphorescence  and  sparkles 
by  day  as  well  as  by  night.  It  is  one  quarter  of  an  inch  long, 
and  is  broad  and  flat. 

Besides  the  myriads  of  free-swimming  copepods,  there  are  para- 
sitic forms  in  great  number.  The  marine  parasitic  forms  are 
commonly  known  as  fish-lice.  They  have  various  habits,  some 
living  as  commensals,  others  attaching  themselves  to  animals 
only  to  be  carried  about  -,  the  true  parasites  live  upon  the  blood 
and  tissues  of  their  hosts,  and  may  fasten  themselves  to  the  exter- 
nal parts  of  the  body  or  to  the  internal  organs.  Whales,  fishes 
of  all  kinds,  mollusks,  starfishes,  jellyfishes,  and  corals,  all  have 
some  form  of  parasite,  and  many  have  several  different  kinds  of 
guests.  It  is  said  that  the  haddock  has  more  than  a  dozen  which 
infest  its  external  and  internal  membranes. 

Nicothoe  is  found  on  the  gills  of  lobsters.  The  truly  parasitic 
forms  are  usually  very  degenerate  and  lose  the  characteristics  of 
their  order. 

ORDER  CIRRIPEDIA 

('"  Curled  feet  "^ 
THE    BARNACLES 

Barnacles  of  the  genus  Balanus  (acorn-shells)  (Plate  LIX) 
are  familiar  objects  on  rocky  shores,  which  they  often  whiten  with 
their  shells,  and  those  of  the  genus  Lepas  are  also  widely  known. 
The  name  of  the  order  is  descriptive  of  their  curled  appendages. 
The  appendages  are  fringed  like  feathers  and  are  drawn  into  or 
protruded  from  the  shell  at  will.  When  extended  they  are  con- 
stantly in  motion,  and  create  currents  which  carry  food  to  the 


BARNACLES 


251 


Balanus.     A,    external    view :    s. 
scutum ;  t,  tergum. 


mouth  of  the  animal,  which  is  dependent  upon  such  food  as  comes 
within  range  of  its  tentacles. 

Their  life-history  is  interesting.  The  young  barnacle,  called  a 
naupUus,  in  no  way  resembles  the  adult..  When  it  emerges  from 
the  egg  it  is  a  free  and  independent  animal,  with  one  eye,  three 

,  pairs  of  legs,  and  a  single  shell.  It 
swims  about  for  a  while  and  moults 
several  times.  It  then  has  two  eyes,  two 
shells,  and  six  pairs  of  legs.  At  this 
period  it  seeks  a  permanent  home,  and 
attaches  its  anterior  end  to  the  object  it 
selects  by  means  of  its  antennae,  which 
have  become  suckers.  It  makes  its  hold 
secure  by  secreting  a  cement  which 
permanently  fastens  it  to  the  spot.  It 
then  undergoes  metamorphosis,  loses  its  bivalve  shell  and  its 
eyes,  and  attains  its  characteristic  cirrijjeds,  or  curled  feathery 
legs,  and  a  new  shell  covering.  During  these  transformations, 
from  the  time  it  be-  f 

comes  fixed  until  it  at- 
tains its  adult  form, 
the  barnacle  fasts,  liv- 
ing by  the  absorption 
of  its  own  animal  fat. 
Its  food  subsequently 
consists  of  the  minute 
animal  forms  which 
abound  in  the  sea.  Its 
further  growth  is  by 
moulting,  but  parts 
only  of  its  covering 
are    disengaged ;    the 

SneillS  permanent,  and  Balanus.  B,  anatomy  :  a,  antennules ;  ad,  adductor  muscle ;  m, 
if  a  cnnnAaciTT-A  c+Qo>aa  muscles  of  scuta  and  terga;  o,  edge  of  parapet;  ou,  ovary  ;  om,  ovi- 
lUO      feUOOe&biVt!      febdgefe     duct ;  sc,  scutum ;  sfc,  parapet ;«,  tergum  ;  u'O,  female  aperture. 

of  growth  are  marked 

upon  it  by  lines,  as  in  moUusks.  The  lining  of  the  shell,  or  en- 
veloping skin  of  the  animal,  and  also  the  cuticle  of  the  legs  are 


ad    sc 


ov 


TOO 


252  MARINE  INVERTEBRATES 

shed,  and  in  the  spring  of  the  year  these  thin,  glossy  casts  are  found 
in  abundance  floating  on  the  surface  of  the  water  near  the  shore. 

There  are  but  three  orders  of  barnacles,  namely,  those  in  which 
the  shell  is  directly  attached  to  the  rocks,  those  which  are  attached 
to  floating  objects  by  a  long  stalk,  and  those  which  are  parasitic 
on  animals.     A  species  of  the  third  order  infests  the  whale. 

The  older  zoologists  classed  barnacles  with  the  Mollusca,  but  in 
1829  Vaughan  Thompson,  in  the  study  of  their  embryology, 
found  that  they  should  be  classed  with  crustaceans,  in  company 
with  crabs,  shrimps,  and  water-fleas,  with  which  their  immature 
forms  show  direct  relationship. 

Gmi\j^  Lepas 

This  genus  is  commonly  known  as  the  ship-barnacle,  also  as 
the  goose-barnacle.  It  attaches  itself  to  floating  logs  as  well  as 
to  ships,  but  the  latter  form  its  principal  home ;  consequently  it 
is  a  great  voyager,  and,  though  common  everywhere,  is  every- 
where considered  a  stranger.  The  same  species  are  found  on 
ships  coming  from  the  most  remote  and  widely  separated  regions, 
and  so  they  cannot  be  considered  native  to  any  one  locality. 
They  are  wanderers  on  the  deep,  and  grow  in  such  numbers  on 
the  bottoms  of  ships,  especially  of  those  which  sail  in  warm  seas, 
that  they  seriously  impede  the  progress  of  the  vessels.  Aside 
from  diminishing  its  speed,  they  do  a  ship  no  injury. 

There  was  a  tradition,  which  lasted  several  centuries,  that  geese 
were  hatched  from  these  shells,  which  somewhat  resemble  eggs. 
Gerard,  in  the  appendix  to  his  ^^  Herball  or  Generale  Historic  of 
Plants"  (1597),  gives  a  picture  of  shells  of  Lepas  growing  on  a 
tree,  with  geese  falling  from  them  and  swimming  about  in  the 
water  below.  His  description  is  as  follows :  ^^  There  are  f ounde 
in  the  North  parts  of  Scotland  and  the  islands  adjacent  called 
Orchades  certaine  trees  whereon  do  growe  certaine  shell  fishes  of  a 
white  color,  tending  to  russet,  wherein  are  conteined  little  living 
creatures ;  which  shells  in  time  of  maturitie  do  open,  and  out  of 
them  grow  those  little  living  foules  whom  we  call  barnakles,  in  the 
North  of  England  brant  geise,  and  in  Lancashire  tree  geise ;  but 


BARNACLES  253 

the  other  that  do  fall  upon  the  land  do  perish  and  come  to  no- 
thing." He  then  describes  in  detail  the  various  transformations, 
and  ends  with:  '^But  what  onr  eies  have  seen  and  hands  have 
touched  we  shall  declare." 

The  long,  flexible  stalk  of  Lepas  is  its  anterior  end.  Generally 
this  stalk  is  only  half  an  inch  long,  but  in  some  species  it  attains 
the  length  of  a  foot. 

Huxley  describes  the  barnacle  as  a  crustacean  fixed  by  its  head 
and  kicking  food  into  its  mouth  with  its  legs.  The  mouth  has  a 
pair  of  small  mandibles  and  two  pairs  of  maxillae,  the  last  pair 
uniting  to  form  a  lower  lip.  The  thorax  has  six  pairs  of  branched 
appendages.  The  body  is  enveloped  in  a  fold  of  skin,  to  which 
are  attached  five  shell-like  plates.  One  of  these  plates  is  long 
and  narrow,  and  extends  along  the  dorsal  side :  two  are  large  and 
triangular  (the  terga)  5  two  are  small  and  triangular  (the  scuta), 
the  long  point  extending  downward.  These  shells  are  on  the 
free  or  posterior  end. 

Barnacles  have  a  nervous  system,  consisting  of  a  brain  and  a 
chain  of  five  or  more  ganglia,  but  no  special  respiratory  or  circu- 
latory organs  are  known ;  the  cirripeds,  or  feet,  are  supposed  to 
perform  these  functions.  They  have  also  a  food-canal,  a  diges- 
tive gland,  and  excretory  tubes.  The  eggs  are  carried  under  the 
external  fold  of  the  skin  in  flat  cakes. 

L,  anatifera.  The  shell  is  bluish-white,  showing  lines  of  growth 
and  faint  radiating  hnes  emanating  from  the  anterior  basal  angle.  The 
tipper  valves  are  narrow;  the  long  tips  point  downward,  and  the  top  is 
blunted,  leaving  a  space  which  is  occupied  only  by  a  membrane.  Near 
the  apex  of  the  shell,  at  the  back,  is  a  distinct  angle.  The  dorsal  valve 
is  broad,  not  much  compressed,  and  is  sometimes  grooved  lengthwise. 
The  cartilage  of  the  shell  and  the  stalk  adjoining  the  shell  are  orange- 
colored.  The  stalk  is  grayish-brown  and  the  cirri  flesh-colored. 
The  stalk  is  from  one  inch  to  six  inches  long.  The  shell  is  one  inch 
long. 

L.  striata.  Shells  bluish -white ;  valves  sharply  triangular ;  dorsal 
-valve  compressed,  forming  a  ridge ;  lines  radiate  from  the  basal  angle  of 
the  lower  valves  and  from  the  upper  angle  of  the  terminal  valves,  start- 
ing from  the  extreme  end ;  the  margins  have  a  narrow  edge  of  yellow 
cartilage ;  the  stalk  and  cirri  are  of  a  dark  slate-color ;  shell  and  stalk 
are  each  about  an  inch  long. 

L.  peatinata.  Shell  shorter  and  less  compressed  than  in  the  preced- 
ing species )  lines  of  growth  and  radiating  lines  distinct  3  a  decided  line 


254 


MARINE  INVERTEBRATES 


runs  from  anterior  base  to  summit,  a  little  back  of  the  margin  ;  terminal 
end  broadly  obtuse  (truncated) ;  dorsal  valve  much  compressed,  forming 
a  sharp  edge  serrated  with  ten  to  twelve  teeth  and  distinctly  striated 
or  furrowed. 


"B 


m. 
od. 


^,vd 


-~t 


Lepas  anatifera.  A,  the  entire  animal ;  B,  anatomy,  a,  antennule ;  c,  carina ;  cd, 
cement-gland  ;  I,  digestive  gland  ;  m,  adductor  muscle ;  od,  oviduct ;  ov,  ovary ;  p,  ped- 
uncle ;  s,  scutum ;  t,  tergum  and  testis  ;  vd,  vas  deferens ;  7i,  tentacles. 


Genus  Balanus 

Balamis  is  known  as  the  "  acorn-shell/'  or  "  sea-acorn/'  and  is 
found  in  vast  numbers  and  of  all  sizes  between  tide-marks, 
incrusting  rocks  and  the  piles  of  piers.  It  also  may  be  found 
attached  to  floating  objects  or  to  shells,  or  even  to  living  animals, 
but  its  usual  habitat  is  stationary.  Unlike  Lepas,  it  has  no  stalk, 
the  shell  being  directly  attached  to  some  object.  The  body  is 
surrounded  by  a  fold  of  skin,  to  which  are  attached  a  shell  con- 
sisting of  six  or  more  plates  and  a  fourfold  lid,  or  operculum^ 
consisting  of  two  scuta  and  two  terga.  The  operculum  may  be 
called  the  door,  as  the  animal  opens  and  shuts  it  at  will  and 
has  complete  protection  when  it  is  closed.     If  one  taps  a  rock 


:5^g^. 


I 


BARNACLES  255 

incrusted  with  barnacles,  and  holds  the  ear  near,  the  closing  of 
the  many  doors  may  be  distinctly  heard. 

The  development  of  Balamis  from  the  larval  stage,  as  also 
the  anatomy  of  the  adult,  is  similar  to  that  of  Lepas.  When 
covered  with  water  and  unmolested,  there  may  be  seen  over  a  bed 
of  barnacles  thousands  of  tiny  fringed  feet  waving  to  and  fro. 
The  motions  look  like  gestures ;  they  are  perfectly  regular  and 
rapid,  numbering  eighty  to  a  hundred  a  minute.  The  shell 
covering  formed  by  barnacles  on  piles  of  wharves  and  bridges  is 
said  to  be  a  protective  agent ;  otherwise  the  barnacles  seem  to 
have  no  economic  value  in  nature,  as,  unlike  other  animals,  they 
do  not  serve,  except  in  very  small  measure,  as  food  to  other 
classes.  The  tautog  and  perhaps  some  other  fishes  feed  partly 
upon  them.  They  are  sometimes  an  obstacle  to  oyster-culture,  as 
they  fasten  upon  the  objects  intended  for  oyster  embryos,  and, 
growing  faster  than  the  latter,  soon  crowd  them  off.  One  species, 
Coromila  diadema,  fastens  to  the  skin  of  whales.  It  attains  the 
size  of  two  inches  in  diameter.  The  shell  is  half  an  inch  thick 
and  full  of  cavities,  into  which  the  skin  of  the  whale  is  drawn^ 
giving  the  barnacle  a  secure  hold.    (Plate  LIX.) 

B.  balanoides  (Stimp.),  B.  oviilaris  (Gould),  the  rock-barnaele. 
This  is  perhaps  the  most  conspicuous  of  the  barnacles.  It  inhabits  the 
whole  northern  Atlantic  coast,  and  is  so  abundant  that  it  not  only 
whitens  the  rocks  with  a  complete  incrustation  of  shells,  but  the 
animals  are  so  crowded  that  many  of  them  lose  their  normal  shapes  and 
become  greatly  elongated.  When  the  rocks  are  covered  with  water 
they  seem  alive,  on  account  of  the  thousands  of  waving  tentacles.  This 
species  also  incrusts  woodwork  between  tide-marks. 

The  shell  is  small,  white,  and  variable  in  shape ;  sometimes  its  height 
is  less  than  the  diameter  of  its  base ;  again  the  height  is  several  times 
greater  and  the  summit  broader  than  the  base.  In  its  early  stages  the 
valves  are  smooth,  but  later  the  base  is  scalloped  by  four  or  five  grooves. 
The  summit  of  the  plates  is  even  and  blunt.  The  aperture  is  diamond- 
shaped.  Two  valves  of  the  operculum  are  pointed  at  the  tips ;  two 
are  blunt,  making  a  deep  notch  in  the  summit.  These  valves  are  the 
distinctive  feature  by  which  to  recognize  this  species,  which  varies  so 
much  in  outward  form ;  the  species  is  also  distinguished  by  its  mem- 
branous base,  which  does  not  form  a  solid  plate  hke  that  of  other 
species. 

B,  ebumeus,  the  ivory  barnacle.  This  species,  like  B.  halanoides,  is  a 
very  common  barnacle,  and  is  found  on  all  kinds  of  submerged  wood- 
work, whether  fixed  or  floating.     It  is  also  found  on  the  carapace  of 


256  MARINE  INVERTEBRATES 

crabs  and  Limulus,  and  on  mollusks.  It  is  chiefly  found  on  objects  below 
low-water  mark.  It  ranges  from  Massachusetts  Bay  to  Florida.  It  is 
easily  distinguished  from  the  preceding  by  its  low,  broad  form  and 
shelly  base.  The  shell  is  smooth  and  circular  at  the  base,  and  inclines 
backward,  forming  an  oblique  cone  with  a  triangular  opening ;  the  plates 
terminate  in  points  at  the  summit  and  inchne  backward,  the  last  one 
forming  a  kind  of  beak.  The  operculum  is  pyramidal  -,  two  of  its  valves 
have  both  transverse  and  longitudinal  lines  well  defined  at  the  base,  and 
are  coarsely  toothed  at  the  edges;  the  posterior  valves  are  slightly 
grooved  across. 

B,  rugosus  (Gould),  B.  crenatus.  Shell  white,  cylindrical,  some- 
what conical,  rugged,  the  summit  usually  as  broad  as  the  base ;  height 
often  greater  than  diameter ;  aperture  diamond-shaped,  plates  ending  at 
the  summit  in  acute  spreading  points,  the  posterior  plate  folded  and 
curved  like  a  beak ;  plates  rough,  with  coarse,  irregular  ribs  ;  valves  of 
the  operculum  at  the  summit  acute,  with  diverging  points ;  the  points 
striated.  Found  on  shells  and  stones  in  deep  water  and  also  on  bottoms 
of  ships. 

B,  geniculatus.  Shell  dirty  greenish-white,  cone-shaped;  aperture 
about  the  size  of  base ;  shell-plates  triangular,  unequal  in  breadth,  and 
with  alternate  large  and  small  ribs;  the  smaller  ribs  compressed  and 
roughened  on  the  edges  by  the  conspicuous  lines  of  growth  which  run 
across  them ;  depressed  areas  between  the  plates  marked  with  fine  cross- 
lines  ;  front  valves  of  the  operculum  have  coarse  plated  ridges,  which 
incline  over  one  another  and  are  crossed  by  fine  radiating  hues ;  diam- 
eter at  base  one  to  one  and  a  half  inches  ;  height  two  thirds  the  diameter. 
Found  on  pecten  shells,  and  abundant  off  the  coast  of  Maine. 

B.  tintinnabuUim,  Shell  pink  to  purplish,  conical,  with  six  triangular 
plates,  which  are  grooved,  forming  unequal  ribs,  and  crossed  by  distinct 
lines  of  growth  ;  spaces  between  plates  crossed  by  lateral  lines ;  posterior 
valves  of  the  operculum  longer  than  the  others  and  curved  forward, 
resembling  the  beak  of  a  bird  of  prey;  diameter  at  the  base  one  inch; 
height  one  and  a  haK  inches.  Found  in  warm  waters  and  on  vessels 
from  the  South. 

Suborder  rhizocephala 

These  are  parasitic  forms  and  very  degenerate.  Sacculina  lives 
on  crabs,  and  its  term  of  life  is  about  three  years,  during  which 
period  the  afflicted  crab  does  not  moult.  Its  shape  is  that  of  an 
ovoid  sac  on  a  stalk,  which  it  attaches  between  two  segments  of 
the  ventral  surface  of  its  host.  The  stalk  di\ddes  and  ramifies  in 
a  root-like  manner  within  the  body  of  the  crab,  from  whose  vital 
elements  it  absorbs  its  nourishment.  The  roots  spread  like  a 
mycelium  through  the  whole  crab,  even  to  the  claws. 

JPeltogaster  lives  on  hermit-crabs. 


OPOSSUM-SHRIMPS  257 

SUBCLASS   MALACOSTRACA 

This  subclass  comprises  highly  organized  Crustacea^  usually  of 
considerable  size,  having  the  appendages  much  differentiated,  the 
thorax  with  eight  segments,  and  the  abdomen  with  seven  segments. 

ORDER  SCHIZOPODA 

The  name,  meaning  '^  cleft-footed,"  applies  to  the  appendages 
of  the  thorax,  which  are  once-branched  (biramous).  Gills,  when 
present,  are  attached  to  these  feet,  and  hang  freely  in  the  water. 
A  delicate  carapace  covers  the  thorax ;  the  abdomen  is  propor- 
tionately very  large,  often  twice  the  length  of  the  cephalothorax. 
In  Mysis  the  eggs  are  carried  in  pouches  under  the  thorax,  giving 
the  common  name  of  ''opossum-shrimp"  to  this  small,  transparent, 
phosphorescent  crustacean. 


Genus  Mysis 

M,  stemolepis.  About  one  inch  in  length  j  translu- 
cent; antennae  very  long  j  segments  marked _  at  joints 
with  dark  spots ;  the  last  two  segments  terminate  in  a 
stout  spine ;  telson  longer  than  the  sixth  segment ;  the  sides  are  nearly 
straight  and  are  armed  with  spines ;  the  extremity  is  cleft ;  eyes  large 
and  prominent.  Found  abundantly  in  winter  on  the  shores  of  still, 
muddy  bays  and  sounds,  especially  among  eel-grass. 

ORDER  DECAPODA 

('"  Ten-footed  ") 

The  Decapoda  are  named  from  their  ten  walking-legs.  The 
higher  forms  of  crustaceans  belong  to  this  order.  All  the  JDecap- 
oda  have  a  similar  anatomy,  but  are  placed  in  two  subdivisions 

17 


258  MARINE  INVERTEBRATES 

according  to  their  external  form.  In  3Iacrura,  the  first  subdivi- 
sion, belong  the  lobsters,  crawfish,  shrimps,  prawns,  and  hermit- 
crabs,  animals  having  a  long  and  more  or  less  cylindrical  body, 
with  the  abdomen  extended  j  in  Brachyura,  the  second  subdivision, 
are  placed  the  crabs,  animals  having  the  thorax  broad  and  flat, 
and  the  abdomen  bent  under  the  thorax.  The  Becapoda  have 
twenty  segments,  all  of  which,  except  the  last  one,  have,  at 
some  period  of  life,  a  pair  of  appendages.  The  first  two  pairs  of 
appendages,  or,  in  the  stalk-eyed  forms,  the  first  three  pairs,  are 
especially  connected  with  the  senses,  and  are  often  fringed 
with  hairs,  which  are  also  considered  to  have  a  sense-function. 
The  antennules,  or  first  pair  of  appendages  after  the  eye-stalks, 
are  sometimes  divided -into  two  or  three  branches.  At  the  base 
of  the  antennules  are  the  ears.  The  antennce,  or  second  pair  of 
appendages,  are  undivided,  but  are  larger  than  the  first  pair,  and 
are  often  very  long.  At  the  base  of  the  antennae  are  the  renal 
glands.  Both  the  antennules  and  the  antennae  are  slender,  elon- 
gated, movable,  and  full  of  joints.  In  some  species  they  are  greatly 
modified,  as  in  Scijllarus,  where  they  are  developed  into  broad 
swimming-plates  and,  perhaps,  as  shovels  for  burrowing ;  in  some 
amphipods  they  are  used  as  swimming-organs.    (Plate  LX.) 

The  next  six  pairs  of  appendages  are  grouped  about  the  mouth. 
They  are  the  mandibles,  the  maxillm,  and  the  maxilUpeds.  The 
mandibles  are  at  the  mouth-opening,  and,  being  heavy  and  hard, 
are  adapted  to  tearing  and  grinding ;  they  have  a  jointed  attach- 
ment, the  palpus,  whose  office  is  to  keep  the  mandibles  clean. 
The  two  pairs  of  maxillae  are  delicate  and  leaf -like.  The  three 
pairs  of  maxillipeds  grow  gradually  larger,  the  last  pair  being 
very  prominent  and  extending  over  the  other  mouth-parts.  Next 
come  five  pairs  of  walking-feet.  One  or  more  pairs  of  these  feet 
have  pincer-like  ends,  or  claws.  Some  species  have  the  claws  im- 
mensely developed,  as  in  lobsters.  The  claws  are  the  chelce,  and 
the  feet  which  bear  the  chelae  are  termed  the  chelipeds.  The  rest 
of  the  walking-feet  have  generally  single,  hook-like  ends,  but  are 
variously  modified  in  different  species.  The  abdominal  segments 
have  six  pairs  of  appendages,  also  variously  modified.  The  last 
segment  is  without  appendages,  but  often  is  extended  into  a  tail, 


PLATE   LX. 
External  Anatomy  of  a  Lobster. 

C,  carapace;  e,  eye;  g,  gill;  m,  metastoma;  n,  endopodite;  p,  epipo- 
dite ;  x,  exopodite ;  I- VII,  abdominal  segments ;  1,  antennula ;  2,  an- 
tenna ;  3,  mandibles ;  4,  5,  maxillae ;  6,  1,  8,  maxillipeds ;  9,  big  pincer ; 
10-13,  walking-feet. 


SHRIMPS  AND  PRAWNS  259 

or  fin-like  expansion.  The  next  to  the  last  segment,  in  many  forms, 
has  appendages  modified  into  swimming-plates,  which  extend  on 
each  side  of  the  telson,  forming  a  broad,  fan-like  caudal  extremity. 

They  have,  then,  to  correspond  to  the  twenty  segments  of  the 
body,  two  pairs  of  sensory,  six  pairs  of  mouth-,  and  five  pairs  of 
walking-appendages  attached  to  the  cephalo thorax,  and  six  pairs 
on  the  abdomen.  The  terminal  segment,  or  telson,  is  without  ap- 
pendages. The  exopodite  is  present  on  the  maxillipeds,  but  dis- 
appears from  the  walking-feet  in  the  higher  forms. 

In  moulting  the  Macrura  split  in  the  longitudinal  line  down  the 
back  •  in  the  BracJiyura  the  split  occurs  across  the  body  at  the 
point  between  the  thorax  and  the  abdomen. 

Suborder   macrura 

shrimps,  prawns,  lobsters,  crawfish,  and  hermit-crabs 

The  characteristic  features  of  the  Macrura  are  an  elongated  body 
with  the  abdomen  usually  extended ;  a  carapace,  somewhat  cylin- 
drical j  and  the  last  pair  of  appendages  of  the  abdomen  (which 
are  attached  to  the  next  to  last  segment)  united  with  the  last 
segment,  or  telson,  to  form  a  powerful  caudal  fin,  used  for  swim- 
ming backward.  The  creeping  forms  in  moving  walk  forward, 
but  swim  backward. 

FREE-SWEVIMING  FORMS  :   SHRIMPS   AND   PRAWNS 

In  these  animals  the  body  is  compressed  and  the  carapace  is 
not  hard.  The  abdomen  is  very  large  in  proportion  to  the 
cephalothorax,  and  has  a  peculiar  bend.  The  rostrum  is  often 
longer  than  the  thorax.  The  eye-stalks,  antennas,  and  legs  some- 
times attain  extraordinary  length,  and  the  chel«  (claws)  are  not 
always  on  the  first  pair  of  legs.  In  some  species  chelas  are  on 
two  or  three  pairs  of  the  legs.  Above  the  antennae  are  expanded 
antennal  scales,  which,  together  with  the  long  bases  of  the 
antennules  and  very  prominent  eye-stalks,  make  the  head  a  broad 
and  conspicuous  feature.  The  difference  between  shrimps  and 
prawns  is  not  very  well  defined,  the  small  individuals  seeming  to 
be  generally  called  shrimps,  the  larger  full-grown  ones  prawns. 


260    .  MARINE  INVERTEBRATES 

Prawns  are  known  as  crevettes  in  France  and  as  Garnele7i  in 
Germany,  where  they  are  largely  used  as  food.  In  the  United 
States  the  shrimp-fishery  is  an  industry  of  the  South.  On  the 
California  coast  the  fisheries  are  very  extensive  and  are  monopo- 
lized by  the  Chinese. 

Genus  I^enceus 

Pi  setiferus.  This  species  is  about  six  iuches  in  length  when  full- 
grown.  A  ridge  or  crest  extends  along  the  center  of  the  carapace,  and 
terminates  in  a  long,  pointed,  toothed  rostrum,  the  teeth  being  fringed 
with  hair  on  the  inner  side.  The  antennae  are  a  foot  or  more  in  length  -, 
there  are  chelsB  on  the  first  three  pairs  of  thoracic  feet ;  the  swimming- 
feet  and  lateral  margins  of  the  segments  of  the  abdomen  are  fringed 
with  hair ;  and  the  caudal  appendages  are  longer  than  the  telson.  It 
ranges  from  Virginia  southward,  and  is  very  abundant  on  the  shores  of 
the  Southern  States,  where  it  is  gathered  for  the  markets.  The  large 
ones  are  known  as  prawns  and  the  small  ones  as  shrimps. 

J*,  brasiliensis.  This  species  is  associated  with  P.  setiferus,  and,  al- 
though not  so  abundant,  forms  a  part  of  the  shrimp-supply  in  the  fisher- 
ies. It  differs  from  the  former  in  having  a  groove  on  each  side  of  the 
ridge  which  runs  through  the  center  and  whole  length  of  the  carapace. 
The  first  three  pairs  of  feet  are  chelated.  This  shrimp  is  found  as  far 
north  as  Long  Island,  and  often  in  brackish  water,  or  even  where  the 
water  is  quite  fresh. 

Genus  JPalcemonetes 

p.  vulgaris  (Palce- 
Tnon  vulgaris).  Aver- 
age size  one  half  of  an 
inch  in  length;  body 
translucent,  almost  color- 
less, irregularly  spotted ; 
rostrum  as  long  as  cara- 
pace and  toothed  on  the 

Palcemonetes  vulgaris ;  male.  Upper  edge.       It  IS  lOUnd 

among  eel-grass  m  brack- 
water,   and    also  in    pools    and    ditches  on  muddy  shores   from 
Massachusetts  Bay  to  Florida.     Commonly  known  as  prawns. 

Genus  Crangon 

C,  vulgaris,  the  common  sand-shrimp.  It  ranges  from  Labrador  to 
North  Carolina  on  the  Atlantic  coast  and  from  Alaska  to  southern  Cali- 
fornia on  the  Pacific  coast.  It  is  found  in  abundance  on  sandy  shores  at 
low- water  mark,  and  in  shallow  water  below  tide-mark ;  also  among 
rocks  and  seaweeds.  When  left  by  the  tide  it  buries  itself  in  the  sand. 
Its  color  varies  with  its  location,  rendering  it  inconspicuous.    Upon  the 


PRAWNS 


261 


sandy  shores  it  is  translucent,  pale  in  color,  and  often  specked,  closely- 
resembling  the  sand,  while  on  dark,  muddy  bottoms  it  is  much  darker. 
This  is  an  edible  shrimp,  eagerly  devoured  by  fishes ;  it  is  also  gathered 
for  the  markets.  The  body  of  C.  vul- 
garis is  broad  at  the  anterior  end  and 
tapers  to  a  sharp  point  at  the  posterior 
extremity.  A  pair  of  broad,  divided 
appendages  on  the  cylindrical  segment, 
which  is  next  to  the  last  on  the  abdomen, 
together  with  the  sharp  telson,  form 
a  fan-like  swimming -tail.  As  in  all 
shrimps,  the  antennae  are  long  and  have 
plate-like  antennal  scales  at  the  base, 
which  are  fi'inged  with  hairs.  The  man- 
dibles are  long.  The  movable  finger  of 
the  chela  is  folded  across  the  extremity 
of  the  claw. 

C,  franciscfyimm,  the  California 
shrimp.  This  species  is  about  three 
inches  in  length.  It  is  distinguished 
from  C.  vulgaris  by  its  larger  size  and 
by  the  greater  length  of  the  movable 
finger  of  the  chela,  which  folds  parallel 
to  the  side  of  the  claw  instead  of  across 
its  extremity.  Its  color  is  light  or  dark 
yellowish-gray,  mottled.  This  is  the 
shrimp  extensively  gathered  by  the 
Chinese  for  commercial  purposes.  The 
shrimp-meat  is  dried  and  cured,  and 
then  separated  by  blowers  very  much 
as  wheat  is  cleaned.  It  is  exported  to 
Eastern  countries  in  great  quantities, 
the  value  of  the  export  being  estimated  at    ^,  ,     •  ^t,  „v,^  c:h,nr«r.. 

'  \       1    -T       ^      Tin  CVaJigfonrwigraris,  the  common  sand-smimp; 

one  hundred  thousand  dollars  per  annum .  j^aie,  natural  size. 


CREEPING  FORMS:    LOBSTERS  AND  CRAWFISH 


Family  ASTACOiDja 


Genus  Homarus 

There  are  but  three  species  of  this  genus,  which  is  the  most  im- 
portant one  of  all  the  Crustacea.  They  are  R.  vulgaris  of  Europe, 
H.  capensis  of  the  Cape  of  Good  Hope,  and  R.  americanus,  which 
occurs  on  the  eastern  coast  of  the  United  States  from  Labrador 
to  New  Jersey.  The  lobster-fishery  is  one  of  great  importance, 
and  of  such  value  that  it  is  governed  by  stringent  laws.     The 


262 


MARINE  INVERTEBRATES 


annual  catch  on  the  Atlantic  coast  of  North  America  amounts  to 
many  millions  of  lobsters,  the  money  value  of  which  is  very 
large. 


H,  afnericanus,  the  common  lobster  of  the  Atlantic   coast.     The 
characteristic  feature  of  the  lobster  is  its  enormously  developed  chelae, 

or  pincer-claws,  which  are  on  the 
first  pair  of  walking-feet.  Small 
claws  occur  on  the  next  two  pairs, 
and  simple  hooks  on  the  remain- 
ing two  pairs.  The  appendages 
on  the  abdomen  are  divided  (bira- 
mous).  In  the  female  they  are 
used,  excepting  the  last  pair,  for 
holding  the  eggs;  in  the  male 
they  are  greatly  abridged.  The 
appendages  on  the  next  to  last 
segment  are  divided  and  broadly 
flattened,  forming  with  the  telson 
a  powerful  swimming-paddle. 
The  rostrum  is  very  prominent, 
and  has  a  long,  pointed  end, 
shghtly  upturned,  and  several 
spines. 

The  lobster  belongs  to  the 
creeping  forms  of  the  order  j  it 
walks  forward  by  means  of  the 
ten  feet,  but  swims  backward  by 
using  its  caudal  fin.  It  lives  in 
deep  water  on  rocky  bottoms, 
hiding  among  stones,  etc.,  but 
frequents  sandy  shores  as  well. 
It  lives  on  dead  and  decaying 
animal  matter,  and  it  would  seem 
strange  that  its  flesh  is  so  pala- 
table, were  it  not  that  we  know 
that  chemical  combinations  which 
take  place  in  the  assimilation  of 
food  make  one  kind  as  clean, 
when  transformed,  as  another. 
All  the  crustaceans  have  a  sim- 
ilar dietary,  being  scavengers  of 
the  sea ;  yet  flshes  find  them  more 
acceptable  than  other  animal  food,  and  fishes  capable  of  capturing  larger 
prey  subsist  largely  on  the  minute  entomostracans  described  elsewhere. 
The  lobster  is  so  large  that  it  can  easily  be  dissected,  and  will  serve  as  a 
type  of  the  structure  of  Crustacea.  In  dissecting  one  can  follow  the 
descriptions  given  of  the  anatomy  of  Crustacea  on  page  246,  and  will  be 
interested  in  observing  the  beautiful  arrangement  of  the  parts  and  their 
adaptation  to  the  uses  they  serve. 


Homarus  americanus,  American  lobster ;  male. 


LOBSTERS 


263 


The  female  lobster  carries  her  eggs  on  the  abdominal  legs,  to  which 
they  are  glued  by  a  kind  of  cement.  After  the  young  emerge  from  the 
egg,  the  zoese  still  cling  to  the  mother  for  a  Httle  time.  The  lobster 
moults  eight  times  the  first  year,  five  times  the  second,  and  three  times 
the  third  year,  after  which  the  male  moults  twice  and  the  female  once  a 
year.  It  retires  to  some  secluded  spot  for  this  operation,  which  is  at- 
tended with  many  dangers.  The  back  splits  open  longitudinally  and 
the  animal  slowly  withdraws,  leaving  the  shell  complete.  In  preparation 
for  moulting,  the  lime  around  the 


contracted  joints  of  the  chelae  is 
absorbed,  so  that  the  soft  fiesh  can 
pass  through.  Any  injury  to  a 
limb  at  the  time  of  moulting,  or 
which  results  from  fighting  or 
from  any  accident,  is  repaired  at 
successive  moultings,  and  a  lost 
member  is  replaced  by  a  new,  but 
not  always  a  perfect,  one. 


Genus  Panulirus 

P,  interrupttcs.  This  is  the 
California  spiny  lobster,  rock- 
lobster,  or  salt-water  crawfish.  It 
differs  from  the  common  lobster 
Homarus  of  the  Atlantic  coast  in 
having  no  large  claws,  the  first 
pair  of  feet  being  simple  like  the 
rest,  also  in  having  antennas  which 
are  enormously  long  and  very 
large  at  the  base.  The  carapace 
is  beset  with  spines,  and  the  lateral 
margins  of  the  abdominal  segments  end  in  spines, 
among  the  rocks  on  the  southern  California  coast. 

P,  argils  or  atnericanus  resembles  P.  interriiptus,  and  is  found  on 
the  coast  of  Florida. 

Genus  Scyllarus 

Sctjllariis  has  a  broad,  almost  square  carapace,  which  is  uneven 
and  coarsely  granulated;  the  anterior  corners  are  sharp,  the 
posterior  ones  rounded.  The  antennae  are  curiously  modified 
into  broad,  flat,  double  plates  reaching  quite  across  the  straight 
anterior  end  of  the  carapace.  The  under  scales  of  these  modified 
antennae  are  rounded  and  leaf-like,  the  upper  ones  are  pointed. 
The  margins  of  the  abdominal  plates  on  the  ventral  side  are 
toathed,  and  on  the   upper   side   the  first  three   sections  have 


Panulirus  interruptus.  the  spiny  or  rock-lobster. 


This  species  lives 


264  MARINE  INVERTEBRATES 

knobs,  the  third  one  being  the  most  prominent,  and  forming  the 
posterior  extremity  when  the  abdomen  is  folded  in.  The  walking- 
feet  are  all  simple  and  end  in  points ;  the  first  pair  are  the  longest, 
and  the  following  ones  gradually  diminish  in  size.  The  ventral 
surface  is  rough  and  spiny.  The  abdomen  is  of  about  the  same 
length  as  the  carapace.  These  animals  are  found  off  the  Florida 
coast  and  are  caught  in  the  fish-traps.  They  are  uncommon. 
The  very  peculiar  development  of  the  antennae  makes  them  worthy 
of  examination  when  opportunity  offers. 

ANOMALOUS  FORMS:  ANOMURA 

The  anomalous  forms  which  are  intermediate  between  the  sub- 
orders Macrura  and  Br  achy  ur  a  were,  until  recently,  placed  in  a 
suborder,  Anomiira.  The  members  of  this  group  differ  from  one 
another,  and  some  of  them  resemble  in  external  features  mem- 
bers of  the  other  divisions  of  the  suborders,  but  there  is  a  differ- 
ence in  anatomical  structure  which  separates  them  in  the  classifi- 
cation. 

Family  dromidje 

Genus  Hippoconcha 

H,  arcuata.  This  curious  little  crab,  found  on  the  Florida  coast, 
carries  the  half  of  a  bivalve  shell  over  its  back.  Its  fifth  pair  of  thoracic 
legs  are  bent  over  the  back,  and  these,  together  with  the  fourth  pair  of 
legs  and  the  spiny  front  edge  of  the  carapace,  enable  the  crab  to  hold 
the  shell  in  position.  This  crab  was  formerly  classed  with  the  hermits, 
all  of  which  were  originally  called  Bernhardus,  after  the  monk  of  that 
name. 

Family  pagurid^ 

THE   hermit-crabs 

In  these  curious  animals  the  posterior  part  of  the  body  is  not 
protected  by  a  crustaceous  covering,  and  therefore  the  animal 
seeks  protection  by  inserting  its  soft  and  defenseless  abdomen 
into  some  hollow  object,  usually  the  shell  of  a  gasteropod  mol- 
lusk,  as  the  whelk  or  the  periwinkle  {Buccinum,  lAttorina). 
The  hermit-crabs  do  not  always  use  a  shell  for  this  purpose, 
as  they  are  sometimes  found  in  the  tubes  of  plant-stems  or  in 
sponges.     Like  other  organisms  in  the  animal  world,  they  seem 


HERMIT-CRABS 


265 


these 

colu- 

shell, 

crab 


well  fitted  to  make  the  best  of  their  surroundings,  the  body  be- 
coming modified  to  suit  the  peculiar  conditions  under  which  they 
live.  In  those  which  inhabit  shells  the  abdomen  becomes  spiral, 
in  conformity  to  the 
convolutions  of  the 
shell.  All  the  ab- 
dominal appendages 
are  more  or  less 
atrophied ;  the  sixth 
pair  become  like 
hooks,  and 
fasten  to  the 
mella  of  the 
keeping  the 
securely  attached  to 
it.  In  the  female 
some  of  the  abdom- 
inal appendages 
are  hair-like  and  are 
adapted  to  carrying 
the  eggs.  The  tho- 
rax, being  protected, 
is  protruded  from 
the  shell  at  will. 
The  first  pair  of  feet 
are  much  larger  than 
the  others,  and  are 
provided  with  claws  (chelge).  The  first  right  foot  is  usually  much 
larger  than  the  left,  and,  besides  the  usual  functions  of  captur- 
ing and  crushing  prey,  the  claw,  or  hand,  serves  as  an  operculum 
to  close  the  mouth  of  the  shell  when  the  crab  retires  completely 
within  it.  The  small  left  hand  is  shaped  to  fill  out  the  parts  of 
the  opening  not  covered  by  the  right  one,  thus  making  a  close 
fit.  The  next  two  pairs  of  feet  end  in  simple  hooks,  and  are 
used  for  walking  and  dragging  the  crab  along  when  he  travels. 
These  crabs  move  about  very  fast,  and  the  houses  upon  their 
backs  seem  no  encumbrance. 


Pagurus  bernMrdus :  ch,  chela  of  first  right  leg;  lA,  1.5,  fourth, 
and  fifth  legs ;  t,  abdominal  terga ;  up,  last  pair  of  appendages, 
modified  to  fasten  to  the  columella  of  the  shell  in  which  the  hermit 
lives. 


266  MARINE  INVERTEBRATES 

In  some  genera  both  hands  are  alike ;  in  others  the  left  one  is 
the  larger.  In  the  case  of  hermits  which  live  in  tooth-shells,  the 
right  hand  is  cylindrical  in  form,  fitting  the  circular  opening  of 
the  sheU.  The  other  extreme  is  found  in  the  genus  Cancellus, 
where  both  the  chelipeds  and  the  first  pair  of  ambulatory  feet 
are  ingeniously  shaped,  so  that  when  closed  they  form  a  round 
operculum,  or  door,  which  closes  the  way  into  the  compact  sponge 
which  this  crab  has  for  its  carcinoecium,  or  house.  It  is  interest- 
ing to  note  these  differences  and  observe  the  perfection  with 
which  the  feet  are  formed  and  jointed  to  suit  the  openings  of 
different  shells.  Some  genera  show  other  adaptations  to  their 
twisted  houses,  the  eye-stalks  being  uneven  in  length  and  the 
ambulatory  feet  unequal  on  the  opposite  sides.  Besides  this, 
some  species  are  hairy  and  cover  themselves  with  dirt  for  further 
protection.  The  exposed  claws  of  some  hermits  have  a  special 
armature  of  spines,  which  make  a  fringe  of  points  around  the 
opening  of  the  shell  when  the  crab  is  withdrawn. 

As  the  hermit  grows  he  is  occasionally  obliged  to  find  a  new 
or  larger  shell,  and  there  are  amusing  anecdotes  of  the  troubles 
he  experiences  at  these  times  while  house-hunting.  Very  often 
he  tries  several  shells  before  he  finds  one  to  fit.  There  is  a  tradi- 
tion, not,  however,  well  authenticated,  that  if  the  shell  chosen 
happens  to  be  occupied  by  its  natural  owner,  the  crab  tears  out 
and  devours  the  unfortunate  occupant.  If  the  desired  shell  is 
occupied  by  another  hermit  inferior  in  strength  to  himself,  he 
proceeds  to  take  possession  by  violence.  He  then  examines  care- 
fully the  empty  shell,  inserting  his  legs  and  feelers,  and  if  he 
decides  to  occupy  it  he  withdraws  his  abdomen  from  the  old 
shell  and  darts  it  so  quickly  into  the  new  one  that  the  act  of 
transference  is  difficult  to  follow.  After  walking  about  with  the 
new  shell  it  sometimes  proves  to  be  unsatisfactory  and  further 
search  becomes  necessary.  After  it  is  well  domiciled  the  crab  never 
ventures  outside  the  shell  until  it  is  obliged  to  change  again  on 
account  of  growth,  or  because  some  stronger  crab  dispossesses  him. 
The  shells  of  hermit-crabs  serve  frequentty  as  the  home  of  other 
animals  which  live  with  them  a  commensal  life.  The  hydroid 
Sydractinia  polycUna  often  covers  the  exterior  of  such  shells  with  a 
brown,  velvety  growth.     Some  sea-anemones  also  are  commensals 


HERMIT-CRABS 


267 


with  hermits.  Adamsia  paUiata  is  always  found  on  the  shell  oc- 
cupied by  Uupaguriis  ptidemix,  and  never  on  any  other.  This  is  a 
European  form.  On  our  own  coast 
a  red  anemone,  the  Epizoantlius 
americanus,  found  in  deep  water  off 
the  entire  eastern  shore,  fastens  on 
the  shell  occupied  by  the  hermits 
Eupagurus  pubescens  and  U.  hroyeri. 
This  anemone  in  time  absorbs  the 
shell  of  its  host  and  itself  becomes 
its  protector — an  advantage  to  the 
hermit,  who  finds  room  in  the  yield- 
ing polyp-mass  for  its  increasing 
size,  and  feels  no  longer  the  necessity  for  change  of  domicile.  The 
female  hermit  holds  its  eggs  in  the  posterior  feet  until  they  are 
hatched ;  the  young  are  then  released,  pass  into  the  water,  and 
soon  find  shells  for  themselves. 


A  colony  of  sea-anemones  (Epizoanthus 
americanus)  which  had  completely  cov- 
ered and  absorbed  a  shell  occupied  by  a 
hermit-crab  (Eupagurus  pubescens),  which 
still  lived  within  the  cavity.  The  polyps 
are  not  expanded. 


Genus  Pagurus 

JP.  bertihardus.    This  is  a  large  species,  bright  red  in  color,  rough 
and  hairy.     It  inhabits   the  shells  of   Fulgur  carica   or   of  Polynices 

heros.  It  ranges  from  Cape  Cod  north- 
ward, and  is  replaced  on  the  northern 
California  coast  by  P.  alaskensis  and  P. 
aleuticus. 

I*,  pollicaris.  This  hermit  inhabits 
sheUs  similar  to  those  occupied  by  the  last, 
but  is  pale  red  in  color,  and  its  surface  is 
granulated  and  not  hairy.  The  short  joint 
of  the  chela  has  a  broad  angle.  It  ranges 
from  Massachusetts  to  Florida,  and  occurs 
at  low-water  mark  on  rocky  and  shelly 
bottoms  of  bays  and  sounds. 

P,  longicarijws,  A  quick-moving  little 
hermit  with  long  chelipeds,  found  in  small 
shells  at  the  water's  edge  in  quiet  places. 
They  exist  in  great  numbers  and  are 
eaten,  shell  and  all,  by  fish.  This  species  can  be  distinguished  from 
all  others  by  its  very  light  color  and  metallic  luster. 


Pagurus  bernhardiis,  the  hermit-crab. 


Genus  Clibanarius 

C,  vittatus.     This  hermit  is  found  from  North  Carolina  southward 
along  the  edge  of  the  water  and  in  tide-pools.     It  cannot  be  mistaken 


268 


MARINE  INVERTEBRATES 


for  any  other  hermit  common  on  our  coast,  since  it  has  the  very  distinc- 
tive feature  of  white  longitudinal  stripes  on  the  ambulatory  feet.  The 
chelipeds  are  about  equal,  rough  with  tubercles,  and  the  tips  have 
smooth  black  edges.  Body  and  feet  are  quite  hairy.  The  color  is 
brown  and  white. 

Genus  IPylopagurus 

This  genus  is  represented  in  Southern  v^aters  by  several  species. 
One  of  the  most  characteristic  of  them  lives  in  DentaUum,  the 
tooth-shell.  The  outer  surface  of  the  right  hand  is  formed  to 
close  the  shell.  All  the  ambulatory  feet  and  the  very  small  left 
hand  fold  beneath,  leaving  only  the  flat  surface  of  one  hand  ex- 
posed to  view.  Another  species  lives  in  a  shell  covered  with 
polyzoans. 

FaIVULY  CENOBITn).E 

Genus  Cenobita 

C.  diogenes.  This  large  hermit-crab,  found  in  Florida  and  in  more 
southern  waters,  inhabits  the  beautiful  pearly  shell  of  Livona  pica.  It 
lives  on  land  a  part  of  the  year,  but  spends  the  breeding  season  in  the 
water.  It  can  be  distinguished  by  its  land-roaming  habits,  its  large  left 
cheliped,  very  stout  walking-legs,  and  compressed  eye-stalks.  This  spe- 
cies climbs  the  hills,  but  is  more  frequently  met  with  in  low,  shaded, 
marshy  places.     (Plate  LIX.) 

Family  HiPPiDiE 


Genus  JBTippa 

H,  talpoida.  This  animal,  commonly  known  as 
the  ''  sand-bug,"  differs  greatly  in  appearance  from 
a  crab.  When  the  appendages  are  folded  under  the 
carapace  it  somewhat  resembles  an  egg,  the  body 
being  ovate,  about  half  as  broad  as  long,  and  the 
sides  forming  a  nearly  regular  curve.  The  carapace 
is  about  one  and  a  half  inches  long,  convex,  yellowish- 
white,  and  nearly  smooth.  The  abdomen  is  long  and 
pressed  under  the  body,  reaching  nearly  to  the  front. 
The  eyes  are  minute  and  on  the  ends  of  long,  slender 
stalks.  The  antennae  are  plume-like  and  about  as 
long  as  the  carapace.  Hippa  lives  on  sandy  beaches 
at  or  near  low- water  mark,  exposed  to  the  action  of 
the  waves.  It  burrows  with  great  rapidity  into  the 
loose  and  shifting  sands,  using  the  short  and  stout  second,  third,  and 
fourth  thoracic  legs  and  the  appendages  of  the  sixth  abdominal  segment 


Hippa  talpoida,  the 
sand-bug. 


ANOMALOUS  FORMS  269 

for  pushing  and  digging.  Crabs  of  this  species  are  gregarious  and 
may  be  seen  in  great  numbers,  though  but  few  will  be  captured  together 
by  digging,  as  they  rapidly  disappear  beneath  the  sand.  Sometimes  they 
are  found  swimming  about  in  the  tide-pools.  They  seem  to  live  upon 
the  organic  particles  contained  in  the  sand,  which  the^^  swallow,  the 
mouth  not  being  adapted  for  mastication.  This  species  ranges  from 
Cape  Cod  to  Florida.    (Plate  LXI.) 

H,  analoga.  Similar  to  H.  talpoida,  but  broader  and  flatter.  It  is 
bluish  above,  yellowish- white  below,  and  the  fringing  hairs  are  black. 
Found  on  the  California  coast. 

Genus  Albtmcea 

A,  gibhesiL  This  animal  is  found  with  Hipjoa,  and,  like  it,  burrows 
rapidiy  in  the  sand.  Its  general  outline  is  square.  The  surface  of  the 
carapace  is  marked  off  with  denticulated  lines,  which  make  the  back  ap- 
pear as  if  composed  of  plates.  The  front  edge  of  the  carapace  has  a  row 
of  teeth  and  a  prominent  spine  at  the  anterior  angles.  The  abdomen  is 
doubled  under  itself  (not  fitting  into  a  groove  of  the  thorax,  as  in  ordi- 
nary crabs),  this  animal  being  intermediate  between  the  long-  and  the 
short -tailed  forms.  The  eyes  are  on  triangular,  plate-like  stalks.  The 
antennules  are  very  long  and  are  fringed  with  hair.  The  chelipeds  have 
claw-like  joints,  which  close  across  the  straight,  broad  end  of  the  hand. 
The  first  two  pairs  of  walking-feet  have  curious  sickle-like  terminal 
joints.  The  animal  is  about  one  and  a  quarter  inches  long.  Alhuncsa 
does  not  extend  as  far  north  as  Hippa,  its  range  being  from  Georgia 
southward.     (Plate  LXI.) 

Family  porcellanid^ 

The  crabs  of  this  family  are  little  more  than  one  quarter  to 
one  half  of  an  inch  across  the  back.  The  chelipeds  are  broad 
and  flattened.  The  first  three  pairs  of  walking-legs  are  well  de- 
veloped, and  the  fifth  pair  are  very  small  and  are  doubled  over 
the  base  of  the  carapace.  The  sixth  segment  of  the  abdomen 
has  a  pair  of  biramous  appendages,  which,  with  the  telson,  form 
a  swimming-fan. 

Genus  JPorcellana 

J*,  sayana.  Carapace  httle  longer  than  broad  ;  breadth  about  one 
quarter  of  an  inch ;  smooth  ;  has  three  acute  denticulations  between  the 
eyes,  the  middle  one  the  largest  and  depressed  in  the  center  ;  two  dentic- 
ulations on  each  anterior  side ;  chelae  fringed  with  hair  on  the  edges ; 
walking-legs  somewhat  hairy  ;  fifth  pair  of  legs  folded  over  base  of  cara- 
pace ;  color  reddish,  with  white  spots.  This  species  was  once  called  occu- 
lata,  because  of  the  eye-like  spots  over  its  entire  surface.  The  posterior 
part  and  abdomen  have  longitudinal  bands  of  color.  The  claws  are 
marked  like  the  shell.  Found  from  South  Carolina  southward,  often  in 
the  shells  inhabited  by  hermit-crabs.     (Plate  LXI.) 


270  MARINE  INVERTEBRATES 


Genus  Vetrolisthes 

P.  sexspinosus.  Carapace  longer  than  broad  j  breadtli  about  one 
half  of  an  inch ;  space  between  the  eyes  broad,  but  not  divided  into 
three  teeth  as  in  Forcellana  sayana  ;  second  joint  of  the  cheHped  has 
five  broad  teeth  on  its  front  edge  and  five  or  six  small  spines  on  its 
outer  edge ;  fifth  pair  of  legs  doubled  over  base  of  carapace ;  whole 
body  traversed  with  broken  red  lines.  Found  from  South  Carolina 
southward.     (Plate  LXI.) 

J*,  ar^natus.  Carapace  longer  than  broad ;  breadth  about  one  quar- 
ter of  an  inch ;  prominent  and  wide  between  the  eyes  -,  a  small  sharp 
spine  on  each  anterior  side ;  chelipeds  long ;  second  joint  of  chehped 
twice  as  long  as  broad,  with  three  teeth  on  the  front  edge  and  four  or 
five  small  spines  on  the  outer  edge.  Found  on  the  Florida  coast. 
(Plate  LXI.) 

Family  lithodid^ 

The  species  of  this  family  have  a  broad,  ovate,  uneven  body 
and  a  prominent  rostrum.  The  fifth  pair  of  legs  are  rudimentary 
and  are  folded  under  the  carapace  in  the  branchial  chambers,  so 
that  the  crabs  appear  to  have  but  four  1 3gs  on  each  side.  This  is 
the  distinguishing  feature  of  the  f amity,  and  makes  them  easily 
recognized. 

Genus  Lithodes 

L,  inaia.  The  carapace  is  cordate  (heart-shaped),  and  longer  than 
broad,  exclusive  of  the  rostrum.  The  margin  is  recurved  all  around, 
and  is  beset  with  numerous  very  long  spines.  Six  spines  on  each 
anterior  side  margin  are  regular  and  longer  than  the  others.  The  sur- 
face of  the  carapace  is  covered  with  tubercles  and  spines  and  elevated 
in  places.  The  rostrum  is  spiny,  a  third  as  long  as  the  carapace,  and 
has  two  spines  at  the  base,  one  above  the  other,  a  spine  at  each  side, 
two  lateral  spines  near  the  middle,  and  two  terminal  divergent  spines. 
The  chelipeds  are  unequal  and  are  covered  with  spines,  those  on  the 
inner  margin  being  the  longer.  The  color  is  yellowish-red,  lighter 
underneath ;  the  spines  are  darker.  Found  on  the  fishing-banks  off  the 
coast  of  Maine.     (Plate  LXI.) 

Genus  Echidnocerus 

E,  ciharius.  This  curious  crab  has  the  carapace  raised  in  front  into 
a  large  cone-like  elevation  terminating  in ,  a  long  point.  Three  promi- 
nent but  smaller  cones  extend  across  the  center  of  the  back,  and  two  still 
smaller  ones  occur  on  the  posterior  sides  and  in  the  middle  of  the  poste- 
rior margin.  The  whole  surface  of  the  carapace  is  covered  with  coarse 
granulations  arranged  in  rosette-like  groups.  The  chelipeds  and  legs  are 
beset  with  large  tubercles  and  fold  together  in  such  a  manner  that  when 
retracted  the  crab  is  a  close,  compact,  box-like  mass,  with  a  very  rough, 


PLATE   LXI. 

1,  Hippa  talpoida.  2,  Albunsea  gibbesii. 

3.  1,  Porcellana  sayana ;  2,  Petrolisthes  armatus ;  3,  Petrolisthes  sexspinosus. 

4,  Lithodes  maia. 


PLATE  LXII. 


Echidnocerus  cibarius. 
Echidnocerus  foriminatus. 


Cryptolithodes  sitchensis. 
Phyllolithodes  papillosus. 


ANOMALOUS  FORMS  271 

spiny  armature.  The  antennae  are  broad  at  the  base  and  covered  with 
small  spines  on  the  sides  and  upper  surface,  and  the  eye-stalks  are  also 
spiny.  This  crab  sometimes  attains  the  size  of  ten  inches  across  the 
carapace  and  a  weight  of  seven  pounds,  being  among  the  largest  crabs 
known.  It  is  found  at  the  mouth  of  the  Columbia  River  and  along  the 
northwest  coast.     (Plate  LXII.) 

JE,  foriminatus.  This  species  resembles  E.  ciharius  in  the  man- 
ner of  closing  the  feet,  forming  a  compact,  box-like,  spiny  armature. 
The  body  is  more  depressed  than  that  of  the  latter,  and  the  cone-like 
elevations  on  the  back  are  less  prominent.  The  spines  are  hairy.  The 
characteristic  feature  of  this  species  is  a  semicircular  cut  in  the  second 
joints  of  the  chelipeds,  directly  opposite  to  similar  depressions  in  the  first 
walking-legs,  so  that  when  the  feet  are  folded  a  round  hole  is  left, 
through  which  water  flows  freely  to  the  gill- openings,  which  might,  with- 
out these  open  holes,  be  obstructed  by  the  close  folding  of  the  legs 
against  the  carapace.  Found  off  the  California  coast  near  San  Francisco. 
(Plate  LXII.) 

Genus  Acantholithodes 

A,  Jiispidus,  The  whole  body  in  this  species,  including  the  legs,  is 
covered  with  hairy  spines.  The  abdomen  is  broad,  and  covers  about  the 
whole  under  surface  of  the  body,  and  is  also  beset  with  hairy  spines,  but 
they  are  less  prominent  than  those  on  the  upper  side.  The  rostrum, 
terminating  in  spines,  reaches  to  the  tips  of  the  eye-stalks,  which  are 
also  spiny.  The  chelipeds  are  larger  and  longer  than  the  walking-feet  j 
the  latter  taper  to  a  point,  ending  in  a  sharp  nail.  The  shape  of  the  body 
resembles  somewhat  that  of  a  toad.  This  is  a  deep-water  species,  but  it  is 
sometimes  brought  ashore  at  Monterey,  California,  by  fishermen  who  find 
it  in  the  stomachs  of  fishes. 

Genus  Cryptolithodes 

C,  sitchensis.  The  most  striking  characteristic  of  this  singular  spe- 
cies is  the  great  development  of  the  carapace,  which  forms  a  broad,  thin 
shield  extending  beyond  the  body  and  legs,  and  completely  hiding  the 
animal  beneath  it.  The  carapace  is  smooth  and  uneven,  has  a  high  ridge 
through  the  center  of  the  anterior  part,  and  the  sides  are  broadly  ex- 
panded and  bluntly  pointed  at  the  extremity.  The  rostrum  appears  like 
a  small  rectangular  piece  cut  out  of  the  anterior  side  of  the  carapace. 
This  species  is  found  in  the  Strait  of  Fuca.  A  similar  species,  C.  typicus, 
is  found  near  low-water  mark  on  the  surf -washed  rocks  of  the  beach  at 
Monterey,  California.     (Plate  LXII.) 

Genus  Phyllolithodes 

JP,  papillosus.  The  carapace  is  triangular,  about  two  inches  wide  at 
the  base,  and  narrowing  to  a  long,  pointed  rostrum  which  terminates  in  a 
forked  spine.  The  surface  of  the  carapace  is  deeply  depressed  in  parts, 
and  forms  a  heart-shaped  figure  in  the  center.  The  lateral  margins  have 
four  prominent  spines  on  each  side,  the  two  at  the  posterior  ends  being 


272  MARINE  INVERTEBRATES 

thicker  than  the  other  two.  The  abdomen  is  broad,  covering"  the  whole 
under  side  of  the  body,  and  is  marked  olf  with  prominent  raised  ridges 
diverging  from  the  center  Hne.  The  legs  are  all  beset  with  long,  rough 
spines.  Habitat,  the  northwest  coast.  Taken  from  the  stomachs  of  fishes 
ofe  Monterey,  Cahfornia.     (Plate  LXII.) 

Suborder  beachyura 
the  crabs 

This  group  contains  the  true  crabs,  which  are  the  highest  of 
the  Crustacea.  In  form  they  are  quite  the  reverse  of  the  first 
group.  In  the  Jiacr?(ra— except  in  the  anomalous  forms— 
the  body  is  long  and  cylindrical  and  the  abdomen  extended,  but 
in  the  Brachyiira  the  body  is  flat  and  broad  and  the  abdomen 
short  and  reflexed.  Crabs  of  this  suborder  inhabit  all  seas  of  the 
globe,  and  are  found  from  the  shore  to  great  depths.  Some  spe- 
cies live  on  land,  some  on  the  shore,  some  in  deep  water.  Some 
forms  burrow  in  the  sand )  others  live  under  stones  and  boulders, 
or  conceal  themselves  in  crevices  of  rocks  or  in  the  cavities  of 
sponges.  They  are  divided  into  many  families,  and  creep,  climb, 
swim,  or  burrow,  their  structure  being  modified  to  their  respec- 
tive modes  of  life.  There  is  also  great  variation  in  their  shapes 
as  well  as  in  their  color  and  markings.  This  diversity  is  so  great 
and  peculiar  that  it  seems  as  though  each  one  were  more  curious 
than  the  others. 

In  crabs  the  cephalothorax  is  depressed  and  often  broader  than 
long.  The  abdomen  is  relatively  small  and  is  folded  under  the 
thorax,  lying  in  a  groove  which  it  fits  so  perfectly  as  to  be  quite 
hidden  from  above.  The  appendages  of  the  abdomen  are  much 
reduced  in  number.  The  male  has  two  pairs ;  the  female  has  four 
pairs,  which  it  uses  for  carrying  its  eggs.  The  first  pair  of  walk- 
ing-legs are  comparatively  large,  and  end  in  chelae,  or  pinching- 
claws.  The  other  eight  legs  terminate  in  simple  points,  except 
in  the  swimming  varieties,  when  the  fifth  pair  is  flattened  to  form 
fins,  or  swimming-paddles.  The  eye-stalks  are  long  and  fit  into 
sockets  on  the  carapace.  Both  pairs  of  feelers  are  small.  The 
antennules  are  frequently  folded  into  small  grooves.  The  exter- 
nal or  third  pair  of  maxillipeds  are  broad  and  flat,  and  cover  the 
mouth-parts  like  a  lid,  or  operculum. 


CRABS  273 

Crabs,  like  other  crustaceans,  are  scavengers,  living  on  dead  ani- 
mal matter ;  but  the  land  species  are  also  vegetarian  in  diet.  They 
are  great  fighters,  but  are  also  wily,  often  averting  danger  by 
resorting  to  stratagem.  They  are  an  interesting  and  curious 
group,  as  they  possess  a  good  degree  of  intelligence  and  have 
amusing  habits. 

From  the  time  they  leave  the  egg  until  they  attain  the  adult 
form  they  pass  through  several  complete  and  singular  metamor- 
phoses. The  most  marked  forms  are  called  the  Zoea  and  the  Mega- 
lops.  So  little  do  these  resemble  the  adult  that  originally  they 
were  classed  as  distinct  genera  far  removed  from  the  one  to  which 
they  really  belong.  After  the  larva  has  moulted  several  times  it 
appears  as  in  the  illustration  on  page  248— the  last  zoea  stage. 
From  this  it  changes  directly  to  Megalops  ;  the  Zoea,  seeming  to  be 
attacked  with  violent  convulsions,  wriggles  out  of  its  skin  a  full 
Megalops  (page  248).  The  animal  then  has  enormous  eyes,  an  ex- 
tended abdomen,  an  elongated  carapace,  and  swimming-legs.  This 
stage  is  a  short  one,  and  at  the  first  moulting  changes  to  a  form 
nearly  approaching  the  adult.  From  this  time  they  grow  by 
shedding  the  shell  at  certain  periods.  This  shedding  is  supposed 
to  occur  twice  each  summer  until  they  have  reached  full  growth, 
after  which  it  is  probable  that  they  do  not  again  moult ;  for  often 
they  are  found  with  extraneous  organisms,  such  as  barnacles  and 
sponges,  upon  them,  of  a  size  that  must  have  required  a  consider- 
able period  of  time  for  growth.  The  sexes  of  the  same  species 
sometimes  differ  so  much  that  it  is  difficult  to  classify  them. 
Even  naturalists  have  been  led  into  the  error  of  assigning  the 
male  and  female  to  separate  species. 

The  front  side  margins  of  the  carapace  in  many  crabs  are  edged 
with  a  row  of  teeth  or  with  spines,  which  vary  in  number  and 
character  in  different  species.  In  the  spider-crabs  the  whole  sur- 
face of  the  carapace  is  generally  studded  with  tubercles,  spines, 
and  stiff  hairs  of  a  peculiar  character.  This  armature  is  for  pro- 
tective purposes,  and  is  often  used  to  secure  foreign  bodies,  such 
as  algae,  hydroids,  and  polyzoans,  which  the  crabs  place  upon  their 
backs  to  disguise  themselves.  The  burrowing  crabs  are  usually 
smooth.    When  in  motion  the  crab  moves  sideways,  using  the  legs 

18 


274 


MARINE   INVERTEBRATES 


of  one  side  to  pull  with  and  those  of  the  other  side  to  push  with. 
As  all  the  legs  do  not  move  at  the  same  time,  a  continuous  and 
uniform  motion  is  kept  up.  Some  species  move  with  great  rapid- 
ity, notably  the  sand-crab,  Ocypoda  arenaria.  Often  when  pur- 
sued they  will  run  into  the  surf  instead  of  to  their  holes.  The 
common  edible  crab,  Callinectes  scqndus,  of  the  Atlantic  coast,  th^ 
fiddler-crabs,  and  the  spider-crabs  are  among  the  well-known 
representatives  of  Bracliyura. 

Family  portunidje 

SWIMlVnNG   CRABS 

Genus   Carcinides 

C,  mcenas  (M.  J.  Rathbun),  Carcinus  mcenas  (Leach),  the  green 
crab.  This  is  one  of  the  most  common  species  on  the  Atlantic  coast  from 
Cape  Cod  to  New  Jersey,  and  is  very  abundant  in  Vineyard  Sound,  Buz- 
zard's Bay,  and  Long  Island  Sound.  It  is  found  between  tide-marks,  fre- 
quently well  up  on  the  beach,  hiding  under  loose  stones,  also  in  tide-pools 
and  in  holes  and  cavernous  places  on  the  shore.  It  is  from  one  and  a 
half  to  two  inches  long,  and  a  little  more  in  breadth.  It  has  five  acute 
teeth  on  each  side  of  the  anterior  part  of  the  carapace.     Its  color  is  green, 


Carcinides  mcenas,  the  green  crab. 


spotted  with  yellow,  making  it  quite  conspicuous.  The  surface  of  the 
carapace  and  limbs  is  more  or  less  granulated.  The  posterior  feet  are 
flattened  to  form  swimming-paddles.  It  is  a  very  lively  creature  and  has 
reckless  audacity  when  brought  to  bay,  which  justifies  its  specific  name 
(which  implies  frenzy).     The  French  call  it  crahe  enrage. 


CRABS 


275 


GrENUs   Callinectes 

C,  sapidus  (Mary  J.  Rathbun),  C.  hastatus  (Stimpson),  the  blue  crab. 
This  is  the  common  edible  crab  of  the  Atlantic  coast.  It  is  known 
at  the  North  as  the  ''  blue  crab,"  and  at  the  South  as  the  "  sea-crab."  It  is 
found  from  Cape  Cod  to  Florida,  and  after  the  lobster  is  the  crustacean 
which  has  the  greatest  commercial  value,  being  taken  in  immense  quan- 


Callinectes  sapidus,  the  blue  crab. 


titles  for  the  markets,  not  only  when  the  shell  is  hard,  but  immediately 
after  moulting,  before  the  new  shell  has  hardened,  when  it  is  known  as 
the ''  soft-shelled  crab."  It  inhabits  muddy  shores,  and  is  common  in 
bays  and  at  the  mouths  of  estuaries.  The  carapace  is  about  twice  as 
broad  as  it  is  long,  and  has  a  long,  sharp  spine  on  each  side  which  pro- 
jects outward.  This  is  a  distinguishing  feature.  There  are  eight  short 
spines  on  each  side  between  the  long  spines  and  the  eyes ;  then  come 
recesses  for  the  eyes,  and  between  the  eyes  are  four  unequal  teeth  and  a 
small  spine  underneath.  The  chelae  are  large  and  somewhat  unequal  in 
size ;  then  come  three  pairs  of  simple  feet  and  a  fifth  pair,  which  are  flat- 
tened, forming  swimming- organs.  The  margins  of  the  carapace  and 
abdomen  are  fringed  with  fine  hairs,  as  are  also  most  of  the  joints  of  the 
limbs.  The  upper  surface  of  the  body  and  claws  is  dark  green  in  color, 
the  lower  surface  is  dingy  white,  the  feet  blue,  and  the  tips  of  the  spines 
reddish.  The  body  is  compressed,  the  carapace  being  moderately  con- 
vex above,  and  is  covered  with  minute  granulations,  which  are  more  nu- 
merous over  some  portions  than  over  others.  The  abdomen  of  the  female  is 
very  broad  and  fills  the  entire  space  between  the  bases  of  the  posterior 
pair  of  feet.  During  the  spawning  season  it^  is  so  charged  with  eggs 
that  often  it  projects  out  almost  at  right  angle's  with  the  carapace.    The 


276 


MARINE   INVERTEBRATES 


crabs  of  this  species  are  very  active  and  can  swim  rapidly.  They  also 
have  the  habit  of  pushing  themselves  backward  into  the  mud  for  con- 
cealment. They  are  predaceous  and  pugnacious,  and  have  great  strength 
in  their  claws,  which  they  use  with  dexterity.  They  not  only  fight  their 
own  kind,  but  show  a  bold  front  to  all  enemies,  including  man.  The 
average  size  is  six  inches  across  the  carapace. 

Genus    Ovalipes 

O.  ocellatus  (Rathbun),  Platyonichus  ocellatus  (Latreille), 
the  lady- crab  or  sand-crab.  A  species  common  on  sandy  shores  from 
Cape  Cod  to  Florida.  It  is  found  among  the  loose  sands  at  low- water 
mark,  even  on  the  most  exposed  beaches,  and  also  is  abundant  on  sandy 
bottoms  offshore.  At  low-water  mark  it  buries  itself  up  to  the  eyes 
and  antennae  in  the  sand,  where  it  watches  for  prey  and  f oes^  and  quickly 


Ovalipes  ocellatus,  the  lady-crab. 

♦ 

disappears  beneath  the  sand  when  danger  approaches.  It  possesses  the 
power  of  burrowing  in  common  with  other  marine  animals  which  inhabit 
exposed  beaches  of  loose  sand.  By  burying  itself  deep  in  the  sand  it  is 
protected  from  the  action  of  the  breakers.  This  species  is  easily  dis- 
tinguished by  the  color  and  shape  of  its  carapace,  taken  in  connection 
with  its  posterior  swimming-feet.  The  body  is  nearly  as  long  as  it  is 
broad,  with  five  prominent  spines  on  each  side.  The  front  margin  is 
indented  on  each  side  of  a  three-spined  rostrum,  to  form  cavities  for  the 
eyes.  The  first  limbs  are  large  and  have  claws ;  the  posterior  ones  are 
flattened  into  swimming-feet,  and  the  intermediate  three  pairs  are  sim- 
ple in  structure,  ending  in  points.  In  color  it  is  white,  covered  with 
spotted  rings  of  red  and  purple. 


CRABS 


277 


Cancer  irroratiis,  the  rock-crab  ;  male. 


walking  crabs 

Fa]\iily  cancroid.^: 

Genus  Cancer 

Cirrorattis,  the  rock-crab.    This  is  the  common  crab  of  the  New 

England  coast.     It  ranges  from  Labrador  to  South  Carohna,  but  is  rare 

south  of  New  Jersey.     It 

is    found    on    sandy   as 

well  as  on  rocky  shores 

at  and  below  low- water 

mark  and  also  between 

tide -marks,  hiding  among 

rocks,   nearly  buried  in 

sand   or  gravel,  and   in 

tide-pools,  where  some- 
times amusing  combats 

between  the  males  may 

be  seen.     The  carapace 

is     suboval,     one    third 

broader    than  long,  the 

breadth  being  often  from 

three  to  four  inches.   The 

surface  is  granulated  but 

smooth;     the     color    is 

yellowish,  closely  dotted 

with  brown.     The  eyes  are  on  short  stalks  in  deep,  circular  holes,  and 

between  the  eyes  are  small  teeth.      There  are  nine  blunt  teeth  along 

each  side  of  the  front  edge  of  the  carapace.     The  first  pair  of  legs  are 

short  and  stout,  and  terminate  in  claws.     The  four  posterior  pairs  are 

slender  and  end  in  pointed  tips.      This  is  an  edible   crab,  and  it  is 

devoured  by  the  larger 
fishes,  but  does  not  —  al- 
though there  seems  to  be 
no  reason  for  it  —  share 
to  any  extent  a  place  in 
the  markets  with  the  blue 
crab,  CalUnectes  sapidus, 

C,  borealis,  the  Jonah 
crab.  This  crab  resem- 
bles, and  is  frequently 
taken  for,  C,  irroratus. 
It  is  larger  than  the  latter 
in  full  growth,  and  is 
heavier  and  more  mas- 
sive. The  carapace  and 
claws  are  rougher,  the 
granules  being  irregular 
in  size.      The   legs  are 

proportionately  shorter  and  heavier.    The  teeth  on  the  anterior  margins 

are  rounded  in  front,  but  the  posterior  ones  are  sharply  pointed.    In  color 


Cancer  borealis,  the  Jonah  crab ;  male. 


278 


MARINE  INVERTEBRATES 


it  is  brick-red  above  and  yellowish  beneath.  It  inhabits  rocky  shores 
only  and  is  found  at  low  tide  on  the  surface  of  the  rocks,  where  it  is  ex- 
posed to  the  action  of  the  waves  and  also  to  the  attacks  of  birds  of 
prey,  which  feed  upon  it,  while  C.  irroratus,  concealed  under  the  rocks 
in  the  same  locality,  escapes  their  depredations.  This  species  is  supplied 
to  the  Newport  market,  where  it  is  considered  preferable  to  the  blue 
crab.  Its  range  is  from  the  eastern  end  of  Long  Island  to  Nova  Scotia. 
C,  magister.  This  species  inhabits  the  Pacific  coast  and  ranges  from 
Alaska  to  Lower  California.  The  adult  male  is  from  seven  to  nine  inches 
broad  and  from  four  to  five  inches  long.  The  anterior  margin  of  the 
carapace  is  an  almost  regular  elliptical  curve  with  nine  small  teeth  on 
each  side.  At  the  end  of  the  curve  a  large,  pointed  tooth  projects 
directly  outward,  and  from  this  the  carapace  slopes  abruptly  backward, 
giving  a  narrow  posterior  end.     The  surface  of  the  carapace  is  undu- 


Cancer  magister,  the  common  crab  of  the  Pacific  coast ;  male. 

lated  and  covered  with  papillae,  and  is  light  reddish-brown,  shading  to 
lighter  color  in  the  back.  The  color  of  the  legs  and  under  surface  of  the 
animal  is  yellowish.  The  claws  are  toothed  above  and  ribbed  at  the 
sides.  It  inhabits  sandy  bottoms  below  tide-mark  and  is  the  largest  and 
most  important  edible  crab  of  the  western  coast. 

C.  prodtictus,  the  red  crab.  This  species,  like  the  preceding  one,  is 
of  large  size  and  inhabits  the  western  coast  from  Alaska  to  the  Gulf  of 
California.  The  carapace  is  four  and  a  half  inches  in  length,  from  five 
to  seven  in  breadth,  and  somewhat  elliptical  in  outline.  The  teeth  on 
the  anterior  margin  are  distinctly  separate  in  the  adult,  but  in  the 
young  ajDpear  as  wrinklings  of  the  edge  of  the  carapace.  The  posterior 
margins  are  concave.  In  color  the  animal  is  dark  red  above  and  yellow- 
ish beneath  in  the  adults,  but  variable  in  the  young,  sometimes  being 
yellow  spotted  with  red,  or  banded  with  red  and  yellow.  It  inhabits 
rocky  shores.  This  is  an  edible  crab,  but  is  not  taken  for  the  markets, 
C.  magister  supplying  all  demands. 


CRABS 


279 


Cancer  antennarius,  the  California  rock-crab. 


280 


MARINE   INVERTEBRATES 


C  antennarius,  the  rock-crab  of  the  Pacific  coast.  This  species 
of  the  Cahfornia  coast  inhabits  rocky  bottoms  below  low- water  mark. 
The  carapace  is  three  and  a  half  inches  long  by  five  or  six  inches  wide, 
and  dark  purplish -brown  in  color.  The  chelae  are  marbled  with  purplish 
spots  and  are  nearly  smooth.  The  distinguishing  features  of  this  crab 
are  its  large  and  hairy  antennae,  the  hirsute  margins  of  its  abdomen  and 
walking-feet,  and  the  numerous  hairs  on  the  under  side  of  its  body. 

G-ENus  Menippe 

M.  mercenaria,  the  stone-crab.  This  species  lives  in  deep  holes 
in  the  mud  along  the  borders  of  creeks  and  estuaries,  and  also  in  crevices 
between  fragments  of  rock,  in  stone-heaps  and  other   debris,   and  is 


Menippe  mercenaria,  the  stone-crab  ;  male. 


found  from  South  Carolina  to  Texas.  These  crabs  are  edible,  and  in 
some  localities  are  hunted  for  food,  one  manner  of  capturing  them  being 
to  thrust  the  hand  and  arm  into  their  holes  and  drag  them  out,  an  opera- 
tion attended  with  danger  to  the  inexperienced  hunter,  who  is  likely  to 
be  badly  pinched.  They  are  withdrawn  with  difficulty,  as  they  offer  a 
strong  resistance,  bracing  themselves  with  their  claws  against  the  sides 
of  their  holes,  and  often  hold  so  firmly  to  the  rocks  that  they  are  torn 


MUD-CRABS 


281 


apart.  They  are  also  taken  by  a  hooked  iron  which  is  thrust  into  the 
hole;  the  crab  seizes  it  and  is  then  suddenly  jerked  from  its  hole.  The 
adult  measures  about  three  by  four  and  a  half  inches,  and  the  body 
is  from  one  inch  to  two  inches  thick.  One  of  the  chelee  is  larger  than 
the  other,  and  both  are  proportionately  enormously  large,  and  are  tipped 
with  black.  The  terminal  joints  of  the  other  four  pairs  of  legs  are 
thickly  fringed  with  hairs  and  end  in  points  which  seem  like  nails. 


FoRiviER  GrENus  Pauopeus 

Eupanopeus  herbstii,  Eurypanopeus  clepressus,  Weopanopeus 
texana,  Hhithropanopeus  harrisii  (Mary  J.  Eathbun).  These  four 
species,  formerly  all  called  Panopeus, 
are  small  crabs  which  hve  in  the  mud 
and  are  commonly  known  as  mud- 
crabs.  They  are  abundant  under  stones 
in  muddy  places,  and  occur  on  the 
Atlantic  coast  from  Massachusetts  Bay 
to  Florida,  though  they  are  not  com- 
monly met  with  north  of  New  Jerse3^ 
Eupanopeus  herbstii  is  the  largest  one 
of  the  group,  some  of  the  Southern 
ones  measuring  two  inches  across. 
It  is  found  hving  in  mud  at  low-water 
mark,  or  burrowing  in  banks  near 
high-tide  mark.  It  is  dark  ohve- 
brown,  the  claws  broadly  tipped  with 
black.  Eurypanopeus  depressus  is  flat- 
tened above,  and  is  smaller  than  Neo- 
panopeus  texana,  which  is  somewhat 
convex  above.  The  last  two  are  com- 
monly found  together  and  have  similar  habits.  JRhithropanopeus  harrisii 
lives  near  high-water  mark  and  also  in  salt-marshes,  and  is  comparatively 
rare.  The  claws  lack  the  dark  tips  of  E.  herbstii,  and  a  distinct  groove 
follows  the  edge  of  the  carapace. 


Eurypanopeiis  depressus,  the  mud-crab  ;  male, 
natural  size. 


Fainoly  grapsid^ 
Genus  Semigrapsus 

H,  nudus  (Mary  J.  UsLthhun), Il€terogra2:)Sus  niidus  (Stimpson);  JET. 
oregonensis  (Mary  J.  Eathbun),  Heterograpstis  oregonensis  (Stimp- 
son).  These  two  species,  commonly  called  respectively  the  pwrpZe  shore-crab 
and  the  yellow  shore-crab,  are  the  most  abundant  species  of  the  California 
coast.  Hundreds  may  be  fouud  congregated  under  a  single  rock.  They 
range  from  Sitka  to  Lower  California.  H.  oregonensis  literally  swarms  in 
sloughs  of  salt  or  brackish  water,  and  hundreds  of  uplifted  threatening 
claws  confront  the  intruder  who  ventures  on  these  mud-flats  when  the 
tide  is  out.  This  species,  the  yellow  shore-crab,  has  a  nearly  square 
body.    The  anterior  half  of  the  side  margins  has  two  rather  deep  indenta- 


282  MARINE  INVERTEBRATES 

tions,  making  two  spine-like  projections  wbicli  bend  forward.  The 
four  posterior  pairs  of  legs  are  more  or  less  hairy  -,  the  chelce  are  rather 
large  in  proportion.  The  male  is  about  one  inch  across  and  the  female 
is  one  third  less  in  size.  The  general  color  is  yellow.  H.  niidus  is  found 
in  the  same  localities,  and  differs  from  H.  oregonensis  in  being  purple  in 
color,  with  mottled  claws,  and  in  having  the  denticulations  less  pro- 
nounced and  the  walking-feet  devoid  of  hairs.  It  is  also  a  little 
larger.     (Plate  LXIII.) 

Genus  Pacygrapsus 

p.  crassipes,  A  species  very  common  on  the  California  coast  south 
of  San  Francisco.  This  crab  is  similar  in  general  features  to  the 
purple  and  yellow  ones  described  above,  but  is  considerably  larger^, 
and  the  carapace  is  banded  with  color. 


Family  0CYP0DiD.ffi 

Genus  Ocy2yoda 

O,  arenaria,  the  sand-  or  ghost-crab.  The  name  Ocypoda  means 
''  swift-footed,"  and,  as  it  implies,  this  species  is  especially  noted  for  its 
rapidity  of  movement.  These  crabs  are  the  opposite  of  the  strong-armed, 
thick-shelled,  slow-moving  CancroidcB.  An  instance  is  told  of  a  collector 
having  great  difficulty  to  keep  up  at  full  run  with  one  which  he  chased  for  a 
considerable  distance  over  the  sand.  Thej  are  also  dexterous  in  burrowing, 
and  live  in  holes,  often  three  feet  deep,  dug  perpendicularly  into  the 
sand.  They  wander  far  from  their  burrows  when  the  tide  is  out,  and 
every  little  while  raise  their  stalked  eyes  and  stand  on  tiptoe  to  look 
about.  If  alarmed,  they  run  with  great  rapidity  to  the  nearest  burrow, 
or,  if  danger  is  close,  press  themselves  on  the  sand  until  an  attempt  is 
made  to  touch  them,  when  they  again  dart  away  rapidly,  and  in  running 
hold  their  bodies  high,  and  double  and  dodge  so  that  it  is  difficult  to 
catch  them.  Ocypoda  is  colored  almost  exactly  like  the  sand,  and  this 
mimicry,  together  with  its  fleetness,  makes  it  interesting  to  note  and 
difficult  to  capture.  It  inhabits  sandy  beaches  above  tide-mark  from 
Long  Island  to  Brazil,  and  subsists  largely  upon  the  beach-fleas,  which 
inhabit  the  same  localities.  It  springs  upon  them,  very  much  as  a  cat 
catches  a  mouse.  The  carapace  of  this  species  is  almost  square  in  outline, 
and  on  the  anterior  corners  ends  in  a  spine.  A  small  portion  of  the 
carapace  folds  down  like  a  band  between  the  eyes.  On  each  side  of  this 
band,  and  extending  across  the  front,  are  large  grooves  for  the  eye- 
stalks.  The  body  is  about  an  inch  thick ;  the  first  joints  of  the  chelae 
are  toothed ;  one  chela  is  a  little  longer  than  the  other,  and  both  are 
coarsely  granulated.  The  other  four  pairs  of  legs  are  thickly  fringed 
with  heirs.     (Plate  LXIII.) 

Genus  Uca 

U,  fninax(Gelasiniusniifiax),  U,pugnax(Gelasiinuspugnax)f 
U,  piigilator  ( Gelasinius  j^ugilator),  the  fiddler-crabs.   These  species 


PLATE  LXIII. 


Hemigrapsus  nudus. 
Ocypoda  arenaria. 
Libinia  dubia. 


Hyas  araneus. 
Pugettia  gracilis. 
Pitho  aculeata. 


FIDDLER-CRABS  283 

of  fiddler-crabs  occur  on  the  Atlantic  coast.  They  congregate  in 
immense  numbers,  and  excavate  their  holes  in  convenient  localities 
above  the  reach  of  the  tides  —  on  salt-marshes,  far  up  the  estuaries,  and 
along  the  mouths  of  rivers,  even  where  the  water  is  quite  fresh.  The 
males  have  one  claw  very  largely  developed ;  the  other  chela  is  small. 
The  former  is  likened  to  a  fiddle,  the  latter  to  a  bow,  and  this,  toge- 
ther with  the  waving  motion  of  the  large  claw,  gives  them  their  popular 
name.  This  comparatively  enormous  claw  is  a  distinguishing  feature  by 
which  they  are  easily  recognized  without  other  description.  The  female 
has  claws  of  small  and  equal  size.  These  crabs  burrow  holes  in  the 
mud  or  sand  half 
an  inch  to  two 
inches  in  diameter 
and  a  foot  or  more 
in  depth.  The 
upper  part  is  nearly 
perpendicular,  be- 
coming horizontal 
below,  with  a  cham- 
ber at  the  end.  One 
species,  U.  minax, 
constructs  an  arch- 
way over  the  mouth 

of     its     burrow,     in  UcaiGelasimvs)  pugilator,  the  S.d.6leT-crsib;  male. 

which    it    sits    and 

surveys  the  surroundings,  but  quickly  retreats  when  danger  approaches. 
The  crab  makes  its  burrow  by  scraping  up  the  mud  or  sand  and  forming  it 
into  pellets,  which  it  carries  under  the  three  anterior  walking-feet  on  the 
under  side,  using  the  legs  on  the  side  moving  forward,  and  the  fourth 
one  on  the  other  side,  to  chmb  out  of  the  hole.  After  peering  cautiously 
about,  the  crab  emerges,  and  carries  its  load  four  or  five  feet  away 
before  dropping  it;  then  again  looks  about  before  quickly  running 
back ;  and,  finally,  turning  its  stalked  eyes,  looks  in  all  directions  and 
suddenly  disappears,  soon  to  return  with  another  load.  The  burrows 
cover  considerable  areas,  and  the  crabs  are  so  abundant  that  the  marshes 
and  shores  sometimes  seem  to  be  alive  with  them.  When  alarmed,  they 
lift  the  large  claw  and  run  sideways,  after  the  manner  of  all  crabs,  to 
their  holes,  and,  as  many  are  likely  to  retreat  into  the  most  convenient 
one,  the  owner  often  finds  his  burrow  occupied  by  other  tenants,  whom 
he  unceremoniously  proceeds  to  pull  out.  U.  minax  ranges  from  southern 
New  England  to  Florida,  and  lives  on  salt-marshes  farther  away  from 
the  sea  than  the  others,  and  often  where  the  water  is  quite  fresh.  It  is 
larger  than  the  other  species,  and  can  be  distinguished  by  a  red  patch  at 
the  joints  of  the  legs.  It  is  a  vegetarian  in  diet,  living  on  small  algae. 
This  is  the  species  which  constructs  a  little  observation-house  oter  the 
mouth  of  its  burrow.  It  can  live  out  of  water,  and  without  food,  for  several 
days.  U.  pugilator  lives  on  sandy  and  muddy  flats  and  beaches  near 
high-water  mark,  where  the  sand  is  compact  and  somewhat  sheltered, 
and  ranges  from  Cape  Cod  to  Florida.  This  species,  like  U.  minax,  is  a 
vegetarian.  JJ.  pugnax  is  exceedingly  abundant  on  muddy  banks  and 
ditches  of  salt-marshes,  the  banks  being  sometimes  completely  honey- 
combed and  undermined  by  them.    It  ranges  from  Cape  Cod  to  Florida. 


284  MARINE  INVERTEBRATES 


Family  maiid^ 

The  members  of  this  family  are  known  as  '' spider-crabs..'^ 
Their  bodies  are  thick  and  more  or  less  round  in  form,  narrowing 
in  front  to  a  long,  beak-like  projection.  The  surface  is  generally 
rough  and  irregular,  having  tubercles,  spines,  prickles,  and  hairs. 
The  legs  are  long.  These  crabs  are  often  covered  with  seaweeds, 
hydroids,  and  other  organisms,  which  they  gather  with  their  long 
and  flexible  chelipeds  and  place  upon  their  backs,  presumably  to 
conceal  themselves  from  their  enemies.  They  seem  to  select, 
instinctively  or  with  reason,  such  things  as  will  bear  transplant- 
ing, sometimes  using  sponges  and  polyps  which  are  not  destroyed 
by  being  torn  apart,  and  they  also  select  their  dress  with  refer- 
ence to  its  masking  uses.  A  Hyas  covered  with  bright-colored 
algae  was  seen  to  remove  them  and  replace  them  with  sponges, 
when  transferred  to  the  locality  of  the  latter,  where  the 
former  did  not  grow.  The  animal  takes  in  his  claw  the  object 
he  has  gathered,  and  first  holds  it  to  his  mouth,  where  it  is 
moistened  with  a  secretion  of  mucus  or  cement,  and  then  places 
it  on  his  back.  If  it  does  not  hold,  the  operation  is  repeated, 
often  several  times,  a  new  spot  on  the  shell  being  selected  each 
time.  It  has  also  been  found  that  the  coats  of  these  crabs  are 
covered  with  hairs  which  are  differently  arranged  in  different 
genera,  some  being  hooked,  others  serrated,  etc.,  and  that 
these  aid  in  holding  the  transplanted  organisms  in  place.  The 
crab  is  sometimes  so  covered  with  these  growths  as  to  be  entirely 
concealed  beneath  them.  It  is  a  sluggish  animal,  and  inhabits 
shallow  water  along  the  whole  of  the  Atlantic  and  Pacific  coasts 

Genus  Libinia 

L,  dubia,  L.  emarginata.  These  two  species  inhabit  the  Atlantic 
coast,  and  are  found  on  muddy  shores  and  flats,  among  decaying  sea- 
weed, in  eel-grass,  and  even  beneath  the  surface  of  the  mud.  They  are 
covered  with  hairs,  and  sometimes  bave  planted  on  their  backs  algse,  hy- 
droids, and  even  barnacles.  The  legs  of  L.  emarginata  often  spread  a  foot 
or  more.  The  males  are  much  larger  than  the  females.  The  species  ranges 
from  Maine  to  Florida.  L.  duUa  does  not  extend  north  of  Cape  Cod. 
It  is  found  more  commonly  than  L.  emarginata  in  very  shallow  water 


SPIDER-CRABS 


285 


near  shore.     It  is  not  so  thickly  covered  with  spines,  and  has  a  longer 
rostrum,  which  is  also  more  deeply  divided  at  the  end.     (Plate  LXIII.) 

Genus  Hyas 

H,  coarctatus,  the  toad-crab.  This  species  of  spider-crab  is  found 
from  Greenland  to  New  Jersey,  in  shallow  as  well  as  in  deep  water.  Its 
body  resembles  strongly,  both  in  form  and  size,  that  of  a  toad,  hence  its 
common  name.     It  forms  an  important  part  of  the  food  of  the  cod, 

H,  lyratus,  A  toad-crab  of  the  Pacific  coast,  ranging  from  Bering 
Sea  to  Puget  Sound ;  named  from  the  lyre-shape  of  its  carapace. 

H.  araneus.  A  species  which  especially  resembles  a  toad  in  its 
form.    Found  off  the  northern  New  England  coast.     (Plate  LXIII.) 

Genus  Loxorhynchus 

L,  crispatiis,  the  sheep -crab.  This  crab  occurs  on  the  coast  of  south- 
ern California.  The  body  is  thick  and  about  three  inches  across  the 
widest  portion,  and  tapers  to  a  long,  prominent  rostrum.  It  is  covered 
with  long  tubercles  and  spines  and  with  short,  bristly  hairs ;  the  legs 
are  long,  the  chehpeds  stretching  fully  two  feet. 

Genus  Pugettia 

1*,  gracilis.  A  small  spider-crab  found  on  the  Pacific  coast  from 
Alaska  to  Puget  Sound.      Its  body   is  one  half  of  an  inch  wide  and 


Epialtus  productus,  the  kelp -crab ;  female. 


286 


MARINE  INVERTEBRATES 


one  incli  long,  with  prominent  spines  on  the  sides  of  the  carapace,  which 
narrows  in  front  into  a  long  beak  ending  in  two  spines.  It  is  red  and 
green  above,  red  beneath.     (Plate  LXIII.) 

Genus  Stemorhynchtis 

S,  Sagittarius,  This  is  one  of  the  most  delicately  formed  of  the  spider- 
crabs.  The  body  has  narrow  longitudinal  stripes  of  light  and  dark  color. 
It  lives  offshore  from  Cape  Hatteras  southward. 

GrENus  Epialtus 

E,  productus,  the  kelp-crab.  This  crab  inhabits  the  coasts  of  Cali- 
fornia and  Oregon,  and  is  found  among  seaweeds  on  rocks  just  below 
low- water  mark.  The  carapace  is  smooth,  is  quadrate  in  form,  is  about 
two  inches  long  and  broad,  has  two  spines  on  each  side,  and  has  a  promi- 
nent denticulated  rostrum.  This  is  the  most  common  spider-crab  of  the 
Pacific  (California)  coast.  It  is  olive-green,  thus  simulating  in  color  the 
kelp  among  which  it  lives.     (See  page  285.) 

Genus  Pitho 

P:  aculeata.  The  carapace  has  six  spines  on  each  side,  the  middle 
two  being  sometimes  partly  united ;  the  general  outline  is  pentagonal ; 
the  length  about  one  inch.  Quite  common  on  the  Florida  coast. 
(Plate  LXIII.) 


^.^ti^ 


Genus  Lambrus 

i.     pourtalesii, 

the  long-armed 

spider  -  crab.  The 
carapace  is  broader 
than  it  is  long  and 
has  three  elevations 
all  covered  with 
spines.  The  general 
surface  is  pitted  and 
granulated ;  the  ros- 
trum points  down- 
ward ;  the  chelipeds 
are  very  long,  the 
margins  armed  with 
spines;  the  breadth 
of  the  carapace  is 
about  one  and  a  half 

inches;  and  the  length  of  the  chelipeds  is  about  three  and  a  half  inches. 

Its  range  is  from  Cape  Cod  to  Florida,  and  it  lives  among  the  rocks. 

(Plate  LXIV.) 


Lambrus  pourtalesii. 


BOX-  AND  OYSTER-CRABS  287 


Family  calappidje 

Genus  Calappa 

C,  flamma,  the  box-crab.  This  singular  animal  lives  on  sandy  and 
muddy  bottoms  offshore,  from  North  Carolina  southward.  The  cara- 
pace is  broad  and  straight  on  the  posterior  side,  and  is  curved  on  the 
anterior  side,  narrowing  to  the  front.  The  posterior  side  has  promi- 
nent denticulations.  The  body  is  one  and  a  half  inches  thick,  about 
four  to  five  inches  wide,  and  two  to  three  inches  long.  The  chelae  are 
large,  broad,  and  flattened,  and  are  so  arranged  that  when  flexed  they 
fit  closely  together  across  the  front.  When  folded,  and  the  small  legs 
are  withdrawn  under  the  carapace,  the  animal  is  shut  up  as  if  in  a  box, 
and  resembles  a  shell.  When  in  danger  it  closes  its  doors,  as  it  were, 
and  abandons  itself  to  the  waves,  which  often  carry  it  ashore.  The 
crested  claws  resemble  the  head  of  a  cock.     (Plate  LXIV.) 


Family  pinnotheiiiid.s: 

GrENus  JPinnotheres 

P,  ostreunif  the  oyster-crab.  The  female  of  this  species  lives  in  the 
gill- cavity  of  the  oyster,  and  is  particularly  abundant  in  oysters  from 
the  Chesapeake.  The  males  are  seldom  seen,  and  rarely  occur  in  the 
oyster,  but  swim  freely  about.  They 
are  smaller  than  the  female,  have  a 
firmer  shell,  and  are  dark  brown  above, 
with  a  dorsal  stripe  and  two  conspicuous 
spots.  The  under  side  of  the  legs  is 
whitish.  The  female  is  commensal,  at 
least  in  the  adult  form,  and  its  thin, 
whitish,  transparent  carapace  is  tinged 
with  pink.   The  species  JP,  tnaculatufn 

T  •      Ti*-    ..7  IT/  i\         J  •„  j-1,^      Pinnotheres  ostremn,  the  oyster-crab;  male, 

hves  m  Myhlus  edullS  (mussel)  and  m  the  enlarged  four  diameters. 

smooth  scallop,  Pecfen  magellanicus.  The 

oyster-crab  is  a  true  messmate,  audits  presence  in  the  oyster  may  be  ad- 
vantageous in  helping  to  provide  food  for  its  host.  This  crab,  like  the  rest, 
holds  its  eggs  in  the  posterior  feet  until  hatched,  when  the  larvae  leave  the 
parent  and  swim  about  for  a  while.  The  females,  at  the  megalops  stage, 
enter  oysters  —  sometimes  two  enter  the  same  oyster,  but^  seldom  niore 
than  one ;  there  it  remains  permanently,  growing  to  the  size  of  an  inch 
or  more  in  diameter,  and  becomes  a  degenerate.  The  eyes  become 
smaller ;  the  shell  never  hardens,  like  its  allies  which  live  in  open  water ; 
its  limbs  and  chelae  are  weak ;  and  it  has  no  pugnacity,  the  protection 
afforded  by  the  oyster  doing  away  with  the  need  for  the  common  protec- 
tive features  of  its  kind.  Pinnixa  ci/lindrica,  a  related  species,  lives  in 
the  tubes  of  large  annelid  worms  as  a  commensal. 


288 


MARINE  INVERTEBRATES 


ORDER  STOMATOPODA 

Genus  Squilla 

S.  empusa.  This  animal  suggests  somewhat  the  lobster,  though  very 
unlike  it.  The  carapace  is  much  smaller  and  softer,  and  leaves  the  last 
three  segments  of  the  thorax  uncovered.     The  abdomen  is  larger  and 

longer  in  proportion,  while  the  legs 
and  organs  are  quite  different. 
The  whole  body  is  depressed,  in- 
stead of  laterally  compressed.  It 
measures  from  eight  to  ten  inches 
in  length  andtwo  inchesin  breadth. 
Instead  of  chelae,  the  last  joint  of  the 
great  claw  has  six  sharp  curved 
spines,  which  fit  into  sockets  in  a 
groove  on  the  second  joint.  By 
this  singular  organ  they  hold  their 
prey  securely.  The  abdominal 
feet  carry  the  gills.  The  antennal 
scales  are  oblong  and  fringed  with 
hair.  The  antennules  terminate 
in  three  flagella.  The  caudal  ap- 
pendages and  telson  are  long, 
strong,  and  armed  with  spines. 
This  animal  lives  in  burrows  in 
the  mud  below  low-water  mark, 
forming  large,  irregular  holes,  but 
is  frequently  washed  ashore.  In 
color  it  is  pale  yellowish-green, 
each  segment  being  bordered  with 
darker  green  and  edged  with 
yellow.  It  is  found  from  Cape 
Cod  to  Florida. 


ORDER  CUMACEA 

Genus  Diastylis 

D,  quadrispinosiis.  Among 
the  minute  Crustacea  which  swim 
on  the  surface  of  the  water,  this 
species,  with  other  small  forms, 
may  be  captured  by  using  a  muslin 
net.  It  is  a  quarter  of  an  inch 
or  less  in  length.  It  is  easily 
Squilla  empusa,  the  mantis-shrimp.  distinguished  by  its  large  carapace, 

the  posterior  portion  of  which  is 
marked  off  in  transverse  ridges,  the  anterior  end  running  into  a  sharp- 
pointed  rostrum.     It  has  a  long,  slender  abdomen,  the  sections  of  which 


AMPHIPODS  289 

are  distinctly  marked,  and  it  terminates  in  long,  forked  spines,  which 
are  longer  than  the  telson.     It  is  fonnd  from  New  Jersey  northward. 

ORDER  AKTHROSTRACA 
Suborder  amphipoda 

TheAmpMpoda  have  a  laterally  compressed  body, with  gills  on  the 
thoracic  feet  and  an  elongated  abdomen.  The  segments  of  the 
thorax  are  not  united,  nor  covered  by  a  carapace,  but  the  whole 
body  is  covered  with  a  segmented,  polished,  flexible  cuticle.  The 
three  anterior  legs  of  the  abdomen  are  for  swimming-feet,  and 
the  posterior  ones  are  adapted  for  springing.  The  antennae  are 
long  and  hairy.  The  amphipods  comprise  the  beach-fleas  and 
many  other  small  crustaceans  which  abound  between  tide-marks 
on  all  beaches.  Besides  serving  in  no  small  measure  as  food  for 
fishes,  they  are  scavengers  of  the  beach,  and  consume  large  quan- 
tities of  waste  matter.  They  are  sometimes  used  in  preparing 
skeletons  for  anatomical  specimens.  Animals  to  be  skeletonized, 
being  fastened  to  boards  and  anchored  just  below  the  surface  of 
the  water  in  sheltered  places,  are  divested  of  all  flesh  in  a  few 
hours,  and  the  bones  are  more  completely  cleaned  than  if  pre- 
pared by  a  naturalist. 

Genus  Orchestia 

O,  agilis,  the  beach-flea.  These  little  crustaceans  exist  in  countless 
numbers  under  the  masses  of  sea-wrack  on  the  beach.  When  disturbed  they 
jump  about  with  great  agility  by  means  of  the  last 
three  pairs  of  abdominal  feet,  which  are  adapted 
to  this  purpose.  In  color  the  animal  is  brown 
and  much  resembles  the  decaying  seaweeds 
among  which  it  lives  and  upon  which  it  probably 
feeds.    The  antennules  are  short,  the  antennae  ^  ,.  .. 

T  ,  T  ••,ni  'rm  i  OrckesUa  agilis ;  male. 

long,  on  two  long,  jomted  bases.     The  second 

pair  of  feet  in  the  males  terminate  in  chelae.  The  last  abdominal  appen- 
dages are  stiJffi  and  pointed  backward.  The  abdomen  is  curved  under. 
The  length  of  Orchestia  is  half  an  inch  or  less.  Some  species  occur  on  all 
beaches.     0.  agilis  ranges  from  New  Jersey  to  Greenland. 

Genus  Talorchestia 

T.  longicornis  (Talitrus  longicornis).     This  species  is  similar  to 
Orchestia  agilis,  but  is  about  an  inch  lorg  when  mature  and  of  a  paler 

19 


290 


MARINE  INVERTEBRATES 


color.  It  jumps  like  the  latter,  but  not  so  strongly.  It  is  found  among 
the  weeds  and  burrowing  in  the  sand  a  little  below  high- water  mark. 
The  wet  sand  is  often  completely  filled  with  its  holes.  It  can  be  distin- 
guished by  its  very  long  antennae.  Another  species,  T.  fuegalophthalma, 
is  distinguished  by  its  shorter  antennae  and  very  large  eyes.  Both  of 
these  species  are  grayish  in  color  and  closely  resemble  the  sand.  Found 
from  Cape  Cod  to  New  Jersey. 


Gammarus  locusta,  the  scud. 


Genus   Gammarus 

G.  locusta.  The  animals  of  this  genus  are  among  the  largest  of  the 
amphipods.  The  males  are  larger  than  the  females,  sometimes  being 
one  and  a  half  inches  long.  They 
are  abundant  under  stones  and 
Fucus  at  and  near  low-water 
mark.  Although  much  larger 
than  the  beach-fleas,  they  other- 
wise resemble  them.  They  do 
not  jump  like  the  former,  but 
move  rapidly,  lying  .on  the  side, 
and  .in  water  swim  with  the  back 
downward.  Two  pairs  of  the  tho- 
racic feet  are  chelate,  and  three 
pairs  are  longer  than  the  others.  The  feet  on  the  last  segments  of  the 
abdomen  are  stiff  and  turn  sharply  back,  forming  a  part  of  the  tail,  which 
is  used  most  effectively  in  locomotion.  The  antennules  and  antennae  are 
of  about  the  same  length.  Several  species  of  Gammarus  occur  in  the  same 
range,  all  having  the  same  general  characteristics ;  some  have  but  one 
pair  of  chelate  feet ;  the  antennules  are  usually  shorter  than  the  antennae ; 
the  females  of  all  the  species  have  no  chelate  feet.  G.  locusta  ranges  from 
New  Jersey  to  Greenland.  The  color  is  generally  reddish-  or  olive-brown. 
G.  annulatus  is  found  in  the  same  places,  but  usually  a  httle  higher  up 
on  the  beach  ;  it  is  lighter  in  color,  and  has  dark  bands  with  red  spots 
on  the  sides  of  the  abdomen.  G.  mucronatus  occurs  from  Cape  Cod 
to  Florida.   Melita  nitida  is  a  smaller  slate-colored  amphipod  found  in 

some  places  ;  another  is  Mmra  levis, 
which  is  whitish,  with  black  eyes. 

Genus  Chelura 

C  terebrans,  the  boring  amphipod. 
This  little  crustacean  is  associated  in 
its  work  on  submerged  timber  with 
the  isopod  Limnoria  lignorum.  The 
excavations  of  the  latter  are  narrow 
and  cylindrical,  running  down  into 
the  wood,  while  Chelura  makes  larger 
burrows  in  oblique  lines  near  the  sur- 
face, which  give  the  wood  the  appearance  of  having  been  plowed.  It 
is  very  active  and  destructive.  It  feeds  upon  the  wood  into  which  it 
burrows.    Its  color  is  semi-translucent,  thickly  mottled  above  with  pink. 


Chelura  terebrans,  the  boring  amphipod. 


ISOPODS  291 

Genus  Caprella 

C,  geometrica.  These  very  curious  little  animals,  which  are  so  slen- 
der as  to  seem  like  skeletons,  are  found  in  abundance  clinging  to  hy- 
droids,  Folyzoa,  delicate  algae,  or  eel-grass,  or  under  stones  in  tide-pools. 
They  resemble  in  color,  and  often  in  form,  the  objects  on  which  they 
live.  Holding  on  by  the  pos- 
terior feet,  they  extend  the  body 
out  rigidly  or  sway  it  about,  so 
that  they  resemble  little  sticks 
or  branches,  and  often  escape 
detection.      In    walking,     they 

bring   the    hind   feet    up    to    the  Caprella  geometrica. 

front  ones,  doubling  the  body 

into  a  loop  like  the  canker-  or  measuring-worm.     The  appendages  on 

the  anterior  and  posterior  ends  are  furnished  with  chelae  and  hooks ; 

those  of  the  middle  section  are  rudimentary.     This  animal  cannot  be 

mistaken  for  any  other.     C.  geometrica  is  found  from  Cape  Cod  to  North 

Carolina.     Some  of  the  species  of  this  genus  may  be  found  on  every 

coast. 

Suborder  isopoda 

The  isopods  have  an  elongate,  flattened,  but  more  or  less 
arched  body,  composed  of  seven  thoracic  segments  and  a  short 
abdomen  of  six  segments.  The  six  segments  of  the  abdomen 
are  smaller  than  those  of  the  thorax,  and  are  often  more  or  less 
united,  sometimes  into  a  single  piece  with  scarcely  any  trace  of 
division  above ;  but  the  number  of  pairs  of  appendages  is  gener- 
ally six,  showing  the  composite  nature  of  the  apparently  simple 
organ.  The  last  segment,  or  telson,  is  broad  and  has  a  pair  of 
modified  appendages.  The  seven  thoracic  legs  are  not  all  equal, 
as  the  name  would  imply,  but  vary  greatly  in  different  species.  As 
a  rule,  they  are  adapted  to  walking  or  attachment,  and  in  the  fe- 
male some  have  delicate  plates  which  form  brood-pouches.  The 
swimming-feet  fold  under  the  abdomen,  and  in  some  species  are 
inclosed  by  the  first  pair,  which  are  large  and  plate-like,  and  form 
a  complete  cover  for  the  others.  The  isopods  are  a  large  and 
widely  distributed  order,  varying  in  size,  and  are  inconspicuous 
because  they  cling  closely  to  objects.  They  are  retiring  in  habit, 
though  extremely  ferocious. 

The  sow-bugs  or  pill-bugs,  common  in  gardens,  under  leaves  in 
the  woods,  and  under  almost  any  pile  of  rubbish  among  decaying 
vegetable  matter,  are  a  land  species  of  isopods.     Other  species  in- 


292 


MARINE  INVERTEBRATES 


habit  ponds  and  streams  of  fresh  water,  and  still  others  are  found 
along  the  shores  of  all  oceans,  abounding  among  the  marine  vege- 
tation of  the  shallow  waters.  Some  swim  free  in  the  open  sea ; 
others  are  brought  up  from  the  greatest  depths.  Others,  again, 
are  parasites,  and  live  in  the  internal  organs  of  fishes  and  prawns. 
Sometimes  a  prawn  is  found  having  what  appears  like  a  very 
swollen  throat,  which  actually  is  a  little  parasitic  isopod  of  the 
family  Bopyriclm  attached  to  its  gills. 

GrENus   Cirolana 

C,  conchartim.  The  body  consists  of  fourteen  segments,  the  first 
being  the  head,  the  next  seven  the  thorax,  and  the  last  six  the  abdomen. 
On  the  head  are  the  triangular  eyes,  the  antennules,  and 
the  antennae,  and  underneath  is  the  mouth,  which  is 
covered  by  the  maxillipeds.  The  dorsal  surface  is  more 
or  less  rounded.  At  the  bases  of  all  the  segmental  thoracic 
rings  excepting  the  first  one  are  sutures  marking  off  square, 
scale-like  pieces  {epimera).  The  epimera  form  a  border 
to  the  side  margins.  The  legs  are  attached  to  the  epimera, 
which  are,  in  fact,  the  upper  segments  of  the  legs.  The 
first  three  pairs  of  legs  have  a  general  resemblance  to  one 
another,  and  are  directed  forward.  The  last  four  pairs  are 
much  longer  and  flatter,  and  are  directed  backward.  The 
telson,  or  last  segment,  is  triangular,  and  the  square  or 
blunt  apex  is  fringed  with  hairs.  On  the  ventral  surface 
of  the  thorax  in  the  adult  females  there  is  a  long  pouch 
for  the  reception  and  development  of  the  eggs.  This  spe- 
cies is  usually  about  one  and  a  half  inches  in.  length,  but  sometimes  is 
longer.  Its  color  is  yellowish,  with  a  brown  edge  on  the  posterior  margins 
of  the  segments,  somewhat  translucent  in  the  thinner  parts.  It  is  found 
from  Cape  Cod  to  South  Carolina,  swimming  about  in 
shallow  water,  and  is  especially  abundant  in  winter. 

Genus  Limnoria 

L,  Ugnorunif  the  gribble.  This  little  isopod  is  very 
destructive  in  its  habits,  boring  into  submerged  wood- 
work, like  the  ship -worm  {Teredo),  and  doing  great 
damage  to  the  piles  of  wharves,  etc.  It  burrows  to  the 
depth  of  half  an  inch,  and  completely  honeycombs  the 
surface  of  the  wood,  which  then  scales  off  or  rapidly 
decays,  and  is  washed  away  by  the  waves.  The  animal 
then  begins  anew,  and  in  a  short  time,  or  at  the  rate  of 
about  an  inch  a  year,  piles  diminish  in  diameter  where 
Limnoria  is  plentiful,  and  are  finally  destroyed  unless  protected  from 
these  little  crustaceans  by  a  sheathing  of  metal.  Although  considered 
as  pests,  they  have  an  economic  value  not  so  often  recognized,  as  they 
attack  all  driftwood,  and  in  time  entirely  destroy  floating  and  water- 


lAmnoria  lignorum, 
the  gi'ibble. 


ISOPODS 


293 


Sphcerovia  quadridentatum. 


logged  timber,  which  without  their  destructive  agency  might  become 
serious  obstructions  to  navigation.  Limnoria  is  only  the  fifth  of  an  inch 
in  length,  and  its  back  is  covered  with  minute  hairs,  to  which  dirt  usually 
adheres.  It  burrows  with  its  mandibles,  or  jaws,  which  are  chisel-like 
at  the  ends.  Its  habitat  extends  from  a  little  above 
to  a  little  below  tide-marks  throughout  the  whole  At- 
lantic coast. 

Genus  Sphceroma 

S.  quadridentatum.  The  name  of  the  genus 
to  which  this  species  belongs  is  derived  from  the 
peculiar  habit  of  many  of  the  species  of  rolling  them- 
selves into  a  ball  when  alarmed.  The  body  is  so 
constructed  as  to  admit  of  this  singular  change  of 
shape.  The  abdomen  turns  under,  and  the  last 
abdominal  appendages,  together  with  the  narrow 
epimera,  shut  in  the  legs  and  cover  the  ventral 
portions  with  armor.  The  body,  when  extended,  is  an  ellipse  a  little 
over  a  quarter  of  an  inch  in  length  and  half  that  in  breadth.  The  legs 
are  hairy  and  adapted  to  walking.  The  anterior  abdominal  segments 
are  fused  into  one,  but  are  marked  at  the  sides  with  depressed- lines. 
The  abdominal  feet  are  plate-like  and  fringed  with  hairs.  A  slight 
elevation  runs  around  the  margins  of  the  animal  like  a  border.  The 
color  is  variable.  Some  are  a  uniform  slaty  gray ;  others  are  marked 
with  a  longitudinal  patch  of  color  on  the 
back.  It  is  found  from  Cape  Cod  to  Florida 
among  algse  or  rocks,  and  is  easily  recog- 
nized by  its  habit  of  rolhng  itself  into  a 
ball.-  Sphceroma  destructor  is  a  boring 
isopod,  larger  than  Limnoria,  and  is  even 
more  destructive,  since  its  holes  are  larger ; 
but  its  range  is  limited,  or,  at  least,  it  has  so 
far  been  found  only  in  the  St.  Johns  River, 
Florida. 

Genu^  Idotea 

I,  marina  (Linnseus),  !»  irrorata 
(Edwards).  This  species  is  about  one  inch 
long,  and  is  easily  recognized  by  the  ab- 
domen, the  first  three  segments  of  which  are 
narrow  and  terminate  in  acute  teeth,  while  the 
other  three  are  fused  into  one  with  straight 
sides  and  ending  in  three  teeth,  of  which 
the  middle  one  is  the  longest.  The  first  pair 
of  abdominal  feet  are  large,  long,  and  plate- 
Hke,  covering  the  other  feet  and  whole  under 
surface  of  the  abdomen  like  an  operculum. 
The  head  is  nearly  square,  the  eyes  are 
small,  and  the  antennae  have  long  peduncles 
thoracic  feet  are  fringed  with  hair. 


Idotea  marina. 


The  articulations  of  the 

The  color  of  this  species  varies : 

sometimes  it  is  light  or  dark  green,  or  brown  with  black  spots ;  again 


294 


MARINE  INVERTEBRATES 


it  is  striped  longitudinally  with  light  color.  Sometimes  the  stripes  run 
transversely  in  bands  or  spots.  It  is  found  from  New  Jersey  northward 
on  rocky  shores  of  bays  and  sounds,  or  in  eel-grass  on  sandy  shores. 

J.  ochotensis,  A  species  very  siniilar  to  the  preceding,  but  a  httle 
larger,  found  on  the  Pacific  coast. 

I,  metallica.  This  species  is  a  little  smaller  than  I.  marina,  and  dif- 
fers from  it  in  having  the  end  of  the  telson  truncated,  or  straight,  instead 
of  dentate.  The  head  is  nearly  square.  The  body  is  broadest  in  the 
middle  of  the  thorax ;  the  projecting  epimera  give  a  serrate  appearance 
to  the  sides.  The  abdominal  feet  are  inclosed  in  the  operculum-like 
scales  of  the  first  pair  of  feet.  Its  color  is  bright  blue  or  green,  often 
with  a  metallic  luster  when  seen  in  the  water.  It  is  found  swimming 
free  or  floating  in  masses  of  seaweeds  from  Long  Island  northward  and 
also  on  the  Pacific  coast. 

I.  wosnesenskii,  A  common  species  on  the  California  coast,  about 
one  inch  long  and  dark  in  color.  The  abdominal  segments  are  united 
and  bluntly  rounded,  and  each  has  a  small  median  tooth.  The  abdomi- 
nal feet  are  inclosed  by  the  opercular 
feet.  Eggs  and  young  are  carried  in  a 
pouch. 

Genus  Chiridotea 

C,  cmca.  This  species  burrows  be- 
neath the  surface  of  the  sand,  raising  it 
up  into  a  little  ridge,  and  makes  a 
mound  at  the  end  of  the  burrow,  where 
it  may  be  found.  These  trails  are 
common  on  the  wet  sand.  It  imitates 
the  sand  in  color,  and  is  about  half  an 
inch  in  length,  with  a  broad  thorax  and 
narrow  abdomen  terminating  in  a  point. 
It  is  found  on  the  New  England  coast. 

C,  entomon  (Linnseus).  This  species 
of  the  northern  Pacific  coast  is  from  one 
to  three  inches  long.  The  head  has  the 
appearance  of  two.  lobes,  the  sides  hav- 
ing two  rounded  ends.  The  body  is 
broad,  the  abdomen  narrowing  to  a 
pointed  end.  The  last  segments  of  the  abdomen  are  united,  and  the 
abdominal  feet  are  inclosed  by  the  first  pair,  which  extend  over  them 
like  an  operculum.     The  epimera  are  broad,  with  acute  lateral  angles. 


Chiridotea  caeca. 


CLASS    MERISTOMES 
ORDER  XIPHOSURA 


Genus  Limulus 

L,  polyphemus,  the  horseshoe-  or  king-crab.    This  well-known  and 
curious  animal  ranges  along  the  Atlantic  coast  from  Maine  to  Mexico. 


HORSESHOE-CRAB 


295 


It  lives  on  sandy  and  muddy  shores  below  low-water  mark,  where  it  bur- 
rows beneath  the  surface.  At  the  breeding  season  —  May,  June,  and 
July  —  it  comes  ashore  to  deposit  its  eggs  near  high-water  mark.  The 
crabs  come  up  the  beach  in  pairs,  the  male  being  the  smaller  and  riding 
on  the  back  of  the  female,  holding  on  by  short  feet  provided  with  nip- 
pers, which  are  pecuhar  to  the  males.  Sometimes  the  female  is  ac- 
companied by  several  males,  each  one  holding  on  to  the  tail  of  another 
and  forming  a  string  of  animals.  After  the  female  has  deposited  her 
eggs  in  a  hole  excavated  by  her  for  the  purpose,  the  male  covers  them 
with  milt,  and  they  then  return  to  the  water,  leaving  the  eggs  to  be  buried 
in  the  sand  by  the  action  of  the  waves.  The  eggs  hatch  in  July  and 
August,  and  sometimes  the  beach  is  literally  alive  with  the  young  crabs, 
which,  however,  soon  disappear, 
and  are  not  seen  again  until  they 
are  well  grown.  After  the 
spawning  season  the  adults  are 
not  very  often  seen,  but  usually 
their  empty  shells,  abandoned 
in  moulting,  may  be  found  on 
the  shore.  The  horseshoe-crab, 
also  called  king-crab,  is  espe- 
cially interesting  from  the  fact 
that  it  is  the  last  survivor  of 
an  otherwise  extinct  group  of 
animals.  Its  relationships  with 
classes  which  have  become  ex- 
tinct, its  nearest  relatives  being 
fossils,  make  it  difficult  to  class- 
ify definitely  with  existing  forms. 
Formerly  it  was  regarded  as  a 
crustacean ;  now  it  is  classed  by 
some  SiVLthoYBwiththeArachnida, 
along  with  scorpions  and  spi- 
ders. It  has  the  characteristics 
of  both  groups.  There  are  only 
two  known  species  of  Limulus 
in  the  world ;  the  other,  Limu- 
lus moluccamis,  lives  on  the 
eastern  coast  of  Asia.  L.  poly- 
phemus  often  measures  a  foot  in 
diameter.  The  body  is  com- 
posed of  three  parts.  The  front 
portion,  or  cephalothorax,  is 
broad  and  semicircular,  with 
posterior  angles  ending  in 
points.  Near  each  side  of  its 
dorsal  surface  is  a  pair  of  large 
compound  eyes  covered  with 
thickened  cuticle,  and  near  the  center  line  of  the  shell,  at  the  base  of  the 
first  spine,  a  pair  of  small,  simple  eyes.  The  second  portion  is  the  ab- 
domen, and  the  third  a  long,  movable  spine  attached  to  the  last  segment 
of  the  abdomen  and  between  two  terminal  points  of  the  horn-like  covering. 


Under  surface  of  horseshoe-crab,  Limuhis  i?oly- 
phemus :  a,  abdomen  ;  c,  cephalothorax ;  g,  the  first 
gill-bearing  abdominal  appendage ;  m,  mouth ;  o, 
operculum  ;  p,  telson ;  s,  metastoma ;  1-6,  cephalo- 
thoracic  limbs. 


296  MARINE  INVERTEBRATES 

On  tlie  cephalotliorax  are  seven  pairs  of  appendages.  The  first  pair  are 
small  and  lie  in  front  of  the  mouth  -,  these  and  the  four  following  pairs  have 
chelae,  or  claws.  The  sixth  pair  have  no  chelae,  but  at  the  base  have  a  pecu- 
liar process  termed  the  flabellum.  These  six  pairs  of  appendages  surround 
the  mouth,  and  have  bristles  at  the  base  which  serve  as  jaws.  The  sev- 
enth pair  of  thoracic  appendages  are  broad  plates  called  the  operculum, 
which  meet  and  cover  the  abdominal  appendages  to  a  certain  extent. 
The  abdomen  has  five  pairs  of  appendages,  which  are  plate-like  and  re~ 
semble  the  operculum  in  form  and  have  an  upper  and  an  under  piece. 
On  the  posterior  surfaces  of  the  abdominal  feet  are  large,  leaf -like  folds, 
which  are  the  gills.  In  front  of  the  first  pair  of  thoracic  legs  is  a  small 
tubercle  supposed  to  have  an  olfactory  function.  Lim^dus  has  a  blood- 
vascular  system  (the  blood  being  bluish  in  color),  a  nervous  and  a  diges- 
tive system.  It  walks  with  the  thoracic  feet  and  swims  with  the  abdom- 
inal ones.  It  enters  the  sand  by  pushing  in  the  rounded,  anterior  end. 
In  moulting  the  carapace  opens  on  the  front  edge.  Limulus  is  edible,  its 
meat  being,  it  is  said,  as  good  as  that  of  the  lobster.     (Plate  LXIV.) 


CLASS  PANTOPODA  (Lang) 

ORDER   PYCNOGONIDA 

This  order  of  animals,  like  Limulus,  has  no  definitely  deter- 
mined position  in  the  classification  of  marine  organisms.  Abont 
one  hundred  and  fifty  species  of  Pycnogonida  have  been  described, 
of  which  thirty  are  found  on  our  coast  and  are  commonly  known 
as  sea-spiders.  They  are  found  crawling  slowly  over  seaweeds, 
hydroids,  and  sponges,  and  appear  to  be  all  legs,  but,  like  other 
animals,  have  a  digestive,  a  circulatory,  and  a  nervous  system. 
They  are  devoid  of  organs  of  respiration.  The  body  has  a 
cephalothorax,  which  bears  a  conical  suctorial  proboscis  on  the 
anterior  end,  and  on  top  a  prominence  containing  four  eyes.  It 
has  three  pairs  of  appendages,  two  pairs  of  which  are  sometimes 
lacking ;  then  come  three  free  segments  and  a  rudimentary  abdo- 
men. There  is  a  pair  of  short  appendages  bearing  claws  (chelae) 
and  four  pairs  of  long  walking-legs.  The  walking-legs  contain 
a  tubular  outgrowth  of  the  body,  into  which  the  stomach  extends. 
The  egg-sacs  are  in  the  legs,  and  open  at  the  basal  joints.  The 
male  is  provided  with  an  extra  pair  of  legs,  for  the  purpose  of 
carrying  the  eggs  after  they  are  deposited  by  the  female.     The 


Calappa  flamma. 
Lambrus  pourtalesii. 


PLATE  LXIV. 


Calappa  flamma,  claws  open,  showing 

form  of  cockscomb. 
Limulus  polyphemus. 


SEA-SPIDER  297 

ovigerous  legs  are  run  through  sac-like  pockets  and  bent  under 
the  body,  and  thus  the  eggs  are  carried  until  hatched. 

Genus  Phoxichilidiuni 

P,  maxillare.  This  species  is  found  on  the  New  England  coast 
creeping  over  hydroids  and  aseidians.  It  is  purple,  gray,  or  brown  in 
color.    Its  young  take  shelter  in  the  cavities  of  hydroids,  forming  gaUs. 


Phoadchilidium  maxillare,  enlarged. 


VII 

MOLLUSCA 


TABLE   SHOWING  THE  CLASSIFICATION  OF  THE  MOLLUSKS 
DESCRIBED  IN    THIS  CHAPTER 

Phylum 

MOLLUSCA 


Classes 
AMFHINEURA 

(Bilaterally  symmetrical 
molhisks,  having  shell 
composed  of  eight  plates, 
or  devoid  of  shell.  In- 
cluding chitons  and  their 
allies) 


GASTEROPODA 

C  TJnsymmetrical  univalve 
m,ollusks,  usually  spiral- 
ly coiled.  Periivinkles, 
whelks,  snails,  etc.) 


SCAPHOPODA 

(Mollusks  without  head, 
eyes,  or  heart,  with  tri- 
lobed  foot  arid  tubular 
shell  open  at  both  ends. 
The  tooth-shells) 


Orders 

POLYPLACOPHORA 

(Shell  composed  of  eight  plates) 

APLACOPHOBA 

(Devoid  of  shell) 


OPISTHOBRANCHIATA 

(Branchioe,  tvhen  present,    behind 
the  heart) 


Suborders 


PROSOBRANCHIATA 

(Branchice  situated  in  front  of  the 
heart) 


PULMONATA 

(Air-breathing  mollusks) 


TECTISRANCHIATA 

(Branchice  more  or  less 
covered  by  mantle ;  shell 
delicate  and  often  rudi- 
mentary ) 

NUDIBRANCHIATA 

(Devoid      of     shell    and 

mantle,      and      without 

true   branchice) 

BIATOCARDIA 
(  Usually  ttvo  auricles,  tivo 

branchice,  and  two  neph- 

ridia) 

MONOTOCARDIA 
(One    atiricle,   one   bran- 

chia,  one  nephridium) 


300 


MOLLUSKS 


301 


Classes 


PELECYPODA 

(Bilaterally  symmetrical, 
headless,  bivalved  inol- 
lusks.  Mussels,  cockles, 
oysters,  etc.) 


CEPHALOPODA 

(Mollusks  of  high  organi- 
zation, having  a  definitely 
formed  head  surrounded 
by  tentacles ,-  shell,  when 
present,  usually  internal; 
shell,  external  in  nautili. 
Cuttlefishes,  squids,  oc- 
topi,  and  nautili) 

Subclasses 

Tetrabranchiata 

Dibranchiata 


Orders 

/  PROTOBRANCHIATA 

(Gills  form  a  single  pair  of  plume- 
like organs,  each  with  tivo  roivs  of 
flattened  gill-filaments) 

FHIBRANCHIATA 

(Two  pairs  of  plate-like  gills  formed 
of  Y-shaped  filaments) 

PSEUDOLAMELLIBRANCHIATA 

I  ( Gills  plaited  so  as  to  form  vertical 
j  folds) 

I      EULAMELLIBRANCHIATA 

I  (Firm,  basket-ivork  gills,  the  fila- 
\  m,ents  united  by  vascular  connec- 
\   tions) 


OCTOPODA 
DECAPODA 


TERMS    USED    IN    DESCRIBING    MOLLUSKS 

Abductor  muscles :  Muscles  whicli  move  parts  away  from  the 
axis. 

Adductor  muscles :  Muscles  which  draw  parts  together ;  oppo- 
site of  abductor. 

ApeHure :  Opening  of  the  spiral  shell. 

Bilateral  sym.fnetry :  Having  two  equal  sides,  divided   by  a 

central  axis. 

Branchiw:  Grills,  or  breathing-organs;  organs  subservient  to 

respiration  through  water.     Same  as  ctenidia. 

Buccal  m^ass :  The  mouth-parts  as  a  whole ;  the  organ  of  pre- 
hension and  mastication  of  food;  the  pharynx:  present  in  all 
mollusks  except  lamellibranchs. 

Canal :  A  narrow  prolongation  of  the  aperture  of  a  spiral  shell. 

Carinated :  Ridged  as  if  keeled ;  having  a  keel. 

Cinereous :  Ash-gray ;  having  the  color  of  wood-ashes. 

Cirri,  plural  of  Cirrus :  Filamentous  appendages. 

Columella :  An  upright  pillar  in  the  center  of  most  of  the  uni- 
valve shells,  round  which  the  whorls  are  convoluted. 

Concrescent :  Growing  together ;  uniting. 

Cordate :  Heart-shaped. 

Costm,  plural  of  Costa :  Ridges  of  a  shell. 

Crenulated :  Having  a  series  of  notches ;  marked  as  with 
notches,  as  the  indented  margin  of  a  shell. 

Crystalline  style:  A  transparent  gelatinous  substance  of  un- 
known function,  which  fills,  at  times,  the  stomach-parts  of  certain 
mollusks. 

Ctenidia  f  plural  of  Ctenidium:  Gills,  or  breathing-organs, 
adapted  to  water-respiration. 

302 


DEFINITION  OF  TERMS  303 

Decussated:  Crossed;  intersected. 

Dextral :  Having  the  aperture  on  the  right  side  of  the  shell 
when  the  apex  is  upward. 

Epidermis :  The  horny  coating  or  outer  skin  of  some  shells. 

Foot:  The  ventral  surface  of  the  body  on  which  the  animal 
rests  or  moves. 

Fossette :  A  little  hollow  or  pit. 

Fuscous :  Brown  tinged  with  gray ;  swarthy. 

Fusiform :  Tapering  both  ways  from  the  middle. 

Ijam.elliform :  Lamellate  in  structure;  disposed  in  leaf -like 
layers. 

Lingual  ribbon :  The  chitinous  band  of  teeth,  or  rasp,  borne 
upon  the  odontophore;  the  radula. 

IJunule :  An  impressed  area  just  below  the  beaks  of  bivalve  shells. 

Mantle:  A  fleshy  or  membranous  outgrowth  of  the  outer  body- 
wall  ;  also  called  pallium. 

Mantle  cavity :  The  space  between  the  mantle  and  the  body. 

Monoinyarian :  Having  one  adductor  muscle,  as  an  oyster. 

NepJiHdium :  The  renal  organ  of  moUusks,  corresponding  to 
kidneys  in  vertebrates. 

N^ode :  A  knob  or  protuberance ;  also  a  notch  in  the  margin. 

Odon'tophore :  The  lingual  ribbon  bearing  chitinous  teeth. 

Oper'culum :  A  horny  or  shelly  plate  which  serves  to  close  the 
aperture  of  the  shell  when  the  animal  is  retracted. 

Osphra'dia,  plural  of  Osphradium :  Olfactory  or  water-testing 
organs. 

Otocyst :  The  cavity,  or  cyst,  which  contains  the  essential  parts 
of  an  organ  of  hearing. 

Fallial  line:  The  impression  or  mark  made  by  the  mantle,  or 
pallium,  on  the  inner  surface  of  a  bivalve  shell. 

Pallial  sinus :  A  notch  or  recess  of  the  pallial  line ;  the  scar  of 
the  siphon. 

Papillaceous :  Warty ;  studded  with  bosses ;  having  excres- 
cences. 

Ferios'tracum :  Same  as  epidermis. 

Fer'istome :  In  zoology,  mouth-parts  in  general ;  in  conchology, 
the  margin  of  the  aperture  of  the  shell. 


304  MARINE  INVERTEBRATES 

Porcelanous :  Resembling  porcelain. 

Bad'ula :  Same  as  lingual  ribbon. 

Beticidated :  Having  distinct  lines  or  veins  crossing  like  a  net- 
work ;  covered  with  netted  lines. 

Sculpture :  Elevated  or  impressed  marks  on  the  surface ;  mark- 
in  gs  resulting  from  irregularity  of  surface  ;  tracery. 

Sinistral :  Having  the  aperture  of  the  shell  at  the  left ;  opposite 
of  dextral. 

Sinuate :  Curved  in  and  out ;  wavy. 

Siphon:  A  tubular  fold,  or  prolongation  of  the  mantle  forming 
a  tube. 

Spire :  All  the  whorls  of  a  spiral  univalve,  above  the  first 
large  body- whorl. 

Suture :  The  line  of  junction  of  the  successive  whorls  of  a  uni- 
valve shell,  or  the  line  of  closure  of  the  opposite  valves  of  a 
bivalve  shell. 

Teeth:  Tooth-like  projections  on  the  hinge  of  a  bivalve  shell. 

Testaceous  :  Having  a  hard  shell,  as  distinguished  from  crusta- 
ceous,  or  soft-shelled. 

Turbinate :  Shaped  like  a  whipping-top ;  whorled  from  a  broad 
base  to  an  apex. 

Umbilicus :  A  central,  navel-like  depression  in  the  body- whorl; 
a  circular,  more  or  less  central  pit  or  hollow. 

Umbo :  The  beak  of  a  bivalve  shell ;  the  protuberance  of  each 
valve  above  the  hinge. 

Varices,  plural  of  Varix :  Raised  marks  on  the  shell  denoting 
a  former  position  of  the  lip  of  the  aperture,  and  indicating  periods 
of  rest. 

Varicose:  Having  prominent  and  tortuous  formations  on  the 
shell. 

Ventricose :  Having  the  whorls  of  the  shell  swollen  or  strongly 
convex. 

Wliorl:  One  of  the  turns  of  a  spiral  shell.  Body-tvJiorl,  the 
last  whorL 


MOLLUSKS 

WE  now  come  to  another  large  and  important  group  of  ani- 
mals, with  characters  so  peculiar  to  itself  and  differing  so 
radically  from  those  which  distinguish  any  other  class  of  living 
creatures,  that  it  may  be  said  to  occupy  almost  a  unique  position 
in  the  animal  kingdom.  Recent  investigations  have  demonstrated 
that  the  larval  form  of  moUusks  presents  some  remarkable 
points  of  similarity  to  the  embryonic  forms  of  the  Annelida 
and  to  the  larvae  of  some  other  classes  of  lower  organisms. 
This  discovery  is  one  of  the  triumphs  of  embryology  in  its  patient 
search  for  that  connecting-thread  that  weaves  together  all  the 
varying  forms  of  animal  life.  Aside  from  these  subtle  evidences 
of  relationship  revealed  by  the  microscope,  the  moUusks  appear 
to  occupy  a  position  of  considerable  isolation  in  the  biological 
world. 

As  accepted  by  zoologists  to-day,  this  phylum  is  but  the  rem- 
nant of  its  former  self.  Aristotle  considered  all  creatures  with 
a  testaceous  covering  to  belong  to  a  single  family,  and  those 
later  patriarchs  of  biology,  Linnaeus,  Cuvier,  and  Lamarck,  ex- 
tended the  group  to  include  the  greater  part  of  all  the  marine 
invertebrate  animals.  Little  by  little  the  phylum  has  been  shorn 
of  orders  and  classes.  First,  the  worms  and  the  UcMnodermata 
were  separated  into  distinct  phyla ;  then  the  barnacles  were  dis- 
covered to  be  crustaceans,  and  were  accordingly  removed  from 
their  position  as  "  multivalves "  under  the  MoUusca ;  then  the 
tunicates,  or  ascidians,  were  found,  through  the  critical  examina- 
tion of  their  larval  stage,  to  be  merely  masquerading  as  moUusks ; 
and  lastly,  the  brachiopods  have  been  somewhat  reluctantly  re- 
moved from  their  old  position  with  the  mollusks  and  given  the 

20  305 


306  MARINE  INVERTEBRATES 

distinction  of  a  phylum  almost  exclusively  to  themselves :  they 
retain  their  old  associations  only  in  the  name  of  MoUuscoida. 

With  some  exceptions^  all  mollusks  secrete  from  their  outer 
skin,  or  mantle  fold,  a  calcareous  protective  covering,  or  shell. 
This  may  be  either  ''  univalve  "  or  '^  bivalve  "  according  as  it  con- 
sists of  one  or  two  pieces.  This  phylum  includes  all  the 
sea-shells  which  are  so  commonly  found  along  every  ocean  beach,  in 
the  tide-pools,  on  rocks  at  low  tide,  in  estuaries,  and,  indeed, 
wherever  sea- water  is  present.  The  phylum  also  includes, 
as  one  of  its  large  suborders,  all  the  snails  and  slugs  that  are 
to  be  found  crawling  upon  the  land.  These  are  true  mollusks, 
which  differ  essentially  from  their  marine  brethren  onty  in  that 
they  breathe  by  means  of  a  pulmonary  sac  or  lung  instead  of  by 
gills.  There  are  also  many  genera  and  species  of  mollusks  that 
find  their  habitat  only  in  the  fresh  water  of  rivers,  lakes,  or  ponds ; 
curiously  enough,  many  of  these  fresh-water  forms,  like  the 
purely  terrestrial  snails  and  slugs,  are  air-breathers,  possessing  no 
gills  whatever,  and  are  consequently  obliged  to  make  periodic 
visits  to  the  surface  of  the  water  to  obtain  their  necessary  supply 
of  oxygen.  There  are  also  numerous  forms  of  mollusks  that  are 
entirely  deprived  of  a  shell  covering  5  and,  again,  there  are  inter- 
mediate types  between  these  two  extremes  that  produce  only  more 
or  less  developed  rudimentary  shells.  Notwithstanding  these 
variations  in  the  matter  of  a  shell  covering,— an  important  con- 
sideration in  this  phylum,— by  reason  of  their  anatomical  features 
these  ^^ naked"  forms  are  mollusks  quite  as  much  as  are  those 
that  secrete  the  most  highly  developed  tests. 

The  marvelous  beauty  of  sea-shells  and  tropical  land-shells, 
their  almost  infinite  variety  in  form  and  coloring,  has  given  to 
them  an  interest  among  collectors  that  is  very  great.  There  are 
many  wonderful  conchological  collections  in  public  museums  and 
in  private  cabinets.  It  would  well  repay  the  lover  of  beauty  as 
well  as  the  more  serious  student  of  nature  to  examine  carefully 
such  collections  when  opportunity  offers,  for  nowhere  in  the  realm 
of  nature  can  more  exquisite  coloring  and  modeling  be  found.  The 
fact  that  shells  may  be  preserved  for  all  time  without  the  expense 
and  the  vexations  of  preservative  fluids  has  no  doubt  induced  many 


MOLLUSKS  307 

to  choose  this  field  of  natural  history  for  special  study.  But  the 
true  student  of  zoology  does  not  confine  his  investigations  in  this 
phylum  to  considerations  of  the  shell  only,  for  the  protective 
armor  constitutes  only  a  portion,  although  an  important  portion, 
of  the  anatomy  of  the  moUusk.  On  the  same  principle,  it  would 
hardly  suffice  to  examine  only  the  skeleton  of  vertebrate  animals 
in  order  to  become  acquainted  with  the  fishes  or  mammals.  In  a 
sense,  the  testaceous  covering  of  a  mollusk  may  be  likened  to  an 
outer  skeleton. 

The  older  zoologists  were  inclined  to  ignore  almost  entirely 
the  animal  or  ^'soft  parts''  of  mollusks,  and  their  classification 
of  the  phylum  into  "univalve,"  "bivalve,"  and  " multivalve," 
based  upon  shell-characters  alone,  has  since  been  proved  to  be 
wholly  artificial.  The  terms  "univalve"  and  "bivalve"  are,  of 
course,  often  and  correctly  used  to-day  to  designate  mollusks 
possessing  a  single  or  a  double  shell,  such  as  the  common  garden- 
snail,  which  carries  upon  its  back  a  single  spiral  shell,  and,  on 
the  other  hand,  the  oyster  or  clam,  which  is  inclosed  within  two 
valves  which  fit  closely  together.  But  these  terms  are  not 
technically  used,  although  they  do  indicate  in  a  general  way  the 
more  modern  classification.  Even  among  some  comparatively 
recent  conchologists  a  tendency  to  belittle  the  value  of  the 
"  slimy  creature  "  within  the  shell  has  led  to  some  curious  errors 
of  grouping — mistakes  which  more  thorough  and  scientific  in- 
vestigation has  brought  to  light.  In  general,  the  higher  classi- 
fication into  classes,  orders,  suborders,  and  families  is  exclusively 
based  upon  anatomical  features,  and  to  a  large  extent,  also,  is 
that  of  the  genera ;  but  species  are  always  determined  by  their 
shell  or  conchological  characteristics. 

When  a  certain  familiarity  with  the  forms  and  general  ap- 
pearance of  shells  is  gained,  a  glance  at  the  shell  alone  will  almost 
always  suffice  to  place  it  at  once  in  its  true  generic  position,  for, 
along  with  modifications  of  the  animal  itself,  corresponding  modi- 
fications of  the  shell  are  quite  certain  to  take  place.  Hence  a 
fairty  expert  zoologist  should  be  able  to  determine  with  con- 
siderable accuracy  from  an  empty  and  dead  shell  the  anatomical 
features  of  the  animal  that  at  one  time  inhabited  it. 


308  MARINE  INVERTEBRATES 

One  of  the  main  reasons  for  the  special  interest  that  seems  to 
have  attached  to  the  study  of  conchology  is  derived  from  the 
fact  that  the  durability  of  shells  has  caused  their  almost  perfect 
preservation  as  fossils  from  the  very  earliest  periods  of  geological 
time,  thus  furnishing  the  key  to  the  solution  of  many  problems  of 
evolution.  Upon  this  page  of  the  earth's  history  the  letters  are 
sharp  and  clear,  and  geologists  possessing  a  knowledge  of  recent 
forms  of  moUusks  as  well  as  of  their  geographical  distribution 
have  been  enabled  to  read  some  wonderful  stories  of  the  cosmic 
history  of  islands  and  continents. 

GEOGRAPHICAL  DISTRIBUTION 

MoUusks  are  found  in  every  part  of  the  world.  The  arctic 
seas  possess  their  own  characteristic  faun^,  the  more  temperate 
waters  of  Europe  and  of  America  contain  their  own  peculiar 
genera  and  species,  and  the  warm  waters  of  the  tropic  seas  furnish 
the  conditions  favorable  to  the  life  of  an  immense  number  of 
characteristic  forms.  Again,  there  are  the  littoral  species,  that 
live  only  between  tide-marks  and  are  therefore  exposed  to  the 
air  for  a  number  of  hours  each  day ;  some  of  these  live  just  about 
high-tide  mark  and  have  become  almost  terrestrial  in  their  habits, 
while  others  must  be  sought  at  the  point  of  lowest  tide,  where 
for  only  a  short  time  each  day  they  are  deprived  of  their  natural 
element.  Then  there  are  the  shallow- water  forms,  which  never 
appear  above  low-tide  mark  save  when  a  neap  tide  surprises  them ; 
their  range  in  depth  extends  to  about  the  hundred-fathom  line, 
more  or  less.  Beyond  this  depth  to  several  hundred  fathoms 
other  characteristic  forms  appear,  and  from  the  more  profound 
depths  of  mid-ocean  the  dredge  has  brought  to  light  a  host  of 
curious  and  interesting  species. 

It  is  the  temperature  of  the  water  rather  than  the  depth  that 
appears  to  influence  the  distribution  of  marine  mollusks.  Thus, 
certain  species  whose  natural  home  is  in  the  shallow  waters  of  the 
Arctic  Ocean  have  been  taken  in  very  deep  waters  off  the  southern 
coast  of  the  United  States,  the  temperature  conditions  in  both 
stations  being  substantially  the  same.  This  fact,  however,  must 
not  be  too  freely  accepted  as  establishing  a  principle.     Some 


MOLLUSKS  309 

shallow- water  forms  have  been  taken  at  great  depths,  but  in 
general  the  abyssal  fauna  is  a  peculiar  one  that  cannot  well  be 
marked  off  into  geographical  provinces. 

THE   ARCTIC  PROVINCE 

The  east  coast  of  America  is  divided  into  several  molluscan 
faunal  regions.  A  series  of  very-cold-water  forms  belonging  to 
a  circumpolar  region,  called  the  ''  arctic  province,"  are  found  as 
far  south  as  Newfoundland.  On  the  New  England  coast  a  num- 
ber of  these  arctic  species  are  also  found,  urged  south  by  the 
influence  of  the  cold  La<brador  current.  The  most  characteristic 
genera  belonging  to  this  arctic  fauna  which  are  found  upon  the 
Maine  and  Massachusetts  coasts  are  Buccmum,  ClirysodomuSj 
Siplio,  TropJion,  Beta,  Velutina,  Trichotrojns,  Lacuna,  Margarita, 
Pecten,  Leda,  Yoldia,  Astarte,  and  Mya.  Examples  of  all  these 
genera  are  encountered  as  far  south  as  Cape  Cod. 

THE  BOREAL  PROVINCE 

A  ^'boreal  province"  corresponds  with  a  similar  faunal  region 
upon  the  European  shore.  The  mollusks  which  compose  this 
fauna  are  about  three  hundred  in  number,  and  range  along  the 
New  England  coast  from  the  Gulf  of  St.  Lawrence  to  Cape  Cod. 
It  is  a  somewhat  remarkable  fact  that  many  of  these  species  are 
identical  with  English  and  French  forms.  The  striking  genera 
upon  the  American  side  are  Pivrpura,  Littorina,  Polynices  (Liinatia 
and  Neverita),  Acmcea,  Margarita,  Chiton,  Boris,  ^olis,  Mytilus, 
Modiola,  Thracia,  and  Micula. 

THE   TRANSATLANTIC  PROVINCE 

Cape  Cod  has  been  regarded,  until  very  recently,  as  a  sharp 
divisional  point  between  the  boreal  and  the  transatlantic  prov- 
inces, the  latter  faunal  area  extending  down  the  Atlantic  coast  of 
the  United  States  to  southern  Florida.  At  Cape  Cod  the  Labrador 
current  is  deflected  from  the  coast,  and  the  warmer  shore  waters 
south  of  that  point  are  unfitted  for  the  development  of  the  boreal 
forms,  though  some  of  them,  as  we  shall  see,  have  passed  the 


310  MARINE  INVERTEBRATES 

barrier  and  maintain  themselves  very  successfully  at  Martha's 
Vineyard  and  in  Long  Island  Sound.  Some  of  the  species  whose 
natural  habitat  is  south  of  Cape  Cod  are  also  to  be  found  north 
of  that  point,  but  they  do  not  reach  their  full  development  in  the 
colder  waters  of  Massachusetts  Bay. 

The  long  stretch  of  coast-line  from  Cape  Cod  to  Florida  is 
easily  susceptible  of  faunal  subdivision  at  Hatteras,  below  which 
locality  a  decided  mixture  of  Antillean  species  is  apparent.  Be- 
tween LoDg  Island  Sound  and  Hatteras  the  littoral  moUuscan 
fauna  is  disappointing  to  the  collector,  for  the  number  of  species 
is  relatively  small,  and  few  even  of  these  are  entitled  to  any  claims 
to  beauty  of  shell.  The  nature  of  this  coast,  virtually  a  great 
sweep  of  exposed  sand-beach,  is  not  conducive  to  a  varied  or  rich 
fauna.  But  if  this  portion  of  the  transatlantic  province  is  lack- 
ing in  interest  to  the  shell-collector,  it  is  anything  but  disappoint- 
ing to  the  army  of  men  employed  in  the  oyster-  and  clam-fishery. 
It  is  only  within  this  faunal  area  that  the  American  oyster,  Ostrea 
virginica,  the  best  of  the  edible  shell-fish,  finds  its  natural  home, 
and  here  the  oyster-culture  is  most  extensively  carried  on. 

After  storms  the  Jersey  beaches  are  frequently  strewn  with 
Madra,  Tageliis,  Area,  and  Unsis  ;  in  more  sheltered  places  Fulgur 
and  Polynices  {Ltmatia)  are  commonly  met.  These  may  be  ac- 
cepted as  the  most  characteristic  genera  of  this  province. 

Just  south  of  Cape  Hatteras  an  observer  is  struck  with  the 
sudden  change  in  the  appearance  of  the  shells  on  the  beach. 
Cardium,  Cassis,  Bolmm,  Area,  and  Cancellaria  at  once  suggest 
the  West  Indies.  About  the  vicinity  of  Hatteras  the  Gulf  Stream 
approaches  very  near  the  land,  bringing  with  its  warm  waters 
many  wanderers  from  tropical  homes.  From  Beaufort  to  Florida 
there  is  another  long  stretch  of  exposed  and  shifting  sand-beach, 
which  offers  a  scant  return  to  the  collector  of  mollusks. 

THE   CARIBBEAN  PROVINCE 

When  Florida  is  reached  a  new  world  is  opened  to  the  natural- 
ist, for  there  a  better  acquaintance  is  made  with  the  great  Carib- 
bean province,  which,  extending  from  Florida  to  the  northern 
shores  of  South  America,  embraces  all  the  Bahamas,  the  West 


MOLLUSKS  311 

Indies,  the  Gulf  of  Mexico,  and  the  coast  of  Central  America. 
Strangely  enough,  the  mollusks  of  the  west  coast  of  Florida  are 
more  nearly  related  to  those  of  the  transatlantic  province  than 
are  the  shells  of  the  east  Florida  coast.  This  remarkable  fact  in 
geographical  distribution  can  only  be  explained  by  assuming  that 
an  open  waterway  once  existed  across  the  northern  part  of  the 
Florida  peninsula,  connecting  the  Atlantic  and  the  Gulf,  through 
which  a  mingling  of  the  shallow- water  forms  from  Georgia,  the 
Carolinas,  West  Florida,  and  the  Gulf  coast  took  place.  Thus  it 
would  appear  that  when  Florida  was  an  island  the  fauna  of  its 
east  coast,  original^  largely  Antillean,  was  less  disturbed  by  the 
southern  migration  of  American  species.  The  Florida  Keys  are 
essentially  Antillean.  The  Caribbean  or  Antillean  fauna  is  an 
exceedingly  rich  and  varied  one.  Among  the  most  prominent 
genera  which  may  be  encountered  upon  the  Florida  coast  are 
Stromhiis,  Fasciolaria,  Oliva,  MargineUa,  Natica,  Sigaretus,  Littorina, 
Tectarius,  N'eritina,  Meloiigena,  Cardmm,  CaUista,  TeUina,  Lucina, 
and  Cijrena.  In  such  an  extensive  and  rich  faunal  province  one 
must  not  expect  to  find  in  any  given  locality  a  representation  of 
all  the  characteristic  genera.  For  instance,  collections  made  at 
Havana,  at  Nassau,  and  at  Vera  Cruz  would  each  contain  forms 
more  or  less  peculiar  and  local,  but  certain  species  would  be  found 
in  each  collection. 

On  the  west  coast  of  America  quite  the  same  faunal  division 
into  more  or  less  well-marked  provinces  is  to  be  found.  Bering 
Sea  belongs  to  the  arctic  province,  and  contains,  with  Labrador 
and  Greenland,  many  identical  forms. 

THE   ALEUTIAN    PROVINCE 

The  shore  waters  from  the  southern  peninsula  of  Alaska  down 
to  about  Vancouver  comprise  the  Aleutian  province.  Within 
this  area  occvir  some  arctic  species,  notably  the  soft-shell  clam, 
Mya  arenaria,  which  the  fishermen  gather  in  such  large  quan- 
tities for  bait  along  the  Maine  coast.  An  increasing  number  of 
species  common  to  this  west-coast  faunal  region  and  to  the 
boreal  province  of  the  east  coast  are  being  recorded.     Some  of 


312  MARINE  INVERTEBRATES 

these  have  been  introduced  from  the  East  by  the  agency  of 
man,  but  others  no  doubt  have  a  natural  range  through  the  icy 
waters  north  of  America  and  down  through  the  Bering  Sea  into 
the  Pacific. 

THE   CALIFORNIAN  PROVINCE 

The  Californian  province  extends  from  the  neighborhood  of 
Vancouver  to  Cape  St.  Lucas  and  has  about  five  hundred  species. 
The  northern  portion  of  this  area  contains  some  very  charac- 
teristic forms,  together  with  a  good  mixture  of  species  of  more 
northern  habitat  j  it  might  properly  be  regarded  as  a  subprov- 
ince.  From  San  Diego  south  to  the  cape  the  character  of  the 
fauna  gradually  changes;  this  coast-line  of  southern  California 
has  also  been  considered  a  subregion.  The  main  characteristic 
of  the  Californian  province  is  a  large  development  of  Haliotis,  of 
the  patellif orm  mollusks,  and  of  the  chitons.  A  very  few  minutes 
on  any  good  collecting-beach  of  California  would  convince  the 
Eastern  conchologist  that  he  had  entered  upon  an  entirely  new 
field  of  research.  The  most  notable  genera  are  Calliostoma, 
Chlorostoma,  Scurria,  Acmcea,  various  genera  of  the  Chitonidce, 
Purpura,  Monoceras,  AmpMssa,  Worrisia,  OUvella,  Chorus,  and 
Saliotis. 

THE   PANAMIC   PROVINCE 

The  warmer  waters  of  the  Gulf  of  California  belong  to  the 
Panamic  province,  which  extends  down  to  South  America.  This 
is  one  of  the  richest  and  most  interesting  faunas  in  the  world. 
At  Panama  alone,  Mr.  C.  B.  Adams,  a  noted  collector  and 
student  of  conchology,  took  upward  of  four  hundred  species. 
About  eight  hundred  species  are  known  in  the  Gulf  of  California 
alone. 

It  must  be  borne  in  mind  that  these  faunal  provinces  relate  to 
littoral  and  shallow-water  species,  for  the  present  knowledge  of 
deep-water  forms  is  not  sufiicient  to  permit  of  generalization 
upon  their  distribution. 

We  review  here  only  the  conspicuous  forms  along  our  own 
coasts.  It  may  be  well  to  note,  however,  that  in  some  other 
parts   of  the  world  the   development  of  molluscan  life  is  far 


MOLLUSKS  313 

in  excess  of  anything  to  be  foiind  upon  our  shores.  The 
veritable  paradise  of  the  naturalist  is  the  East  Indies.  There 
the  "aristocratic"  genera,  so  called  on  account  of  their  mar- 
velous beauty,  occur  in  their  highest  development  —  Yoluta, 
Mitra,  OUva,  Conns,  and  the  various  murices.  There  also  are  to 
be  found  the  pearl-oysters,  Meleagrina  margaritifera,  that  yield 
their  valuable  harvest,  and  the  giant  clam,  Tridacna  gigas,  which 
measures  sometimes  five  feet  in  length.  Over  eight  thousand 
species  of  mollusks  are  described  from  this  surpassingly  rich 
region,  yet  this  vast  province,  as  compared  with  the  American 
and  European  shores,  has  been  but  superficially  exploited  by  the 
naturalist.  In  whatever  part  of  the  world  a  natui-ahst  may 
find  himself,  there  is  always  a  tempting  array  of  molluscan  life 
to  attract  him.  Each  fauna  possesses  features  peculiar  to  itseK, 
and  from  the  point  of  ^dew  of  the  true  naturalist,  the  more 
somber-hued  and  conventionally  formed  mollusks  of  Northern 
shores  are  no  less  interesting  than  the  gorgeously  tinted  and 
fantastically  shaped  species  of  the  tropics.  From  any  faunal 
province  of  our  own  country  one  may  readily  gather  all  forms 
necessary  to  furnish  ample  material  for  study  from  which  one 
may  acquire  an  excellent  idea  of  the  biological  features  of  the 
entire  phylum. 

STATION  AND  HABITS   OF  THE   MOLLUSCA 

The  word  "station"  is  used  to  indicate  the  nature  of  the  sur- 
roundings which  an  animal  chooses  as  most  suited  to  his  well- 
being.  Some  groups  of  mollusks,  like  the  littorinas,  the  trochids, 
the  purpuras,  and  the  majority  of  those  having  pateUiform  shells, 
generally  live  on  rocks  above  low-tide  mark ;  other  genera,  like 
Buccinmn,  SipJio,  and  Chrysodomiis,  prefer  rocky  or  gravelly  ground 
below  low-tide  mark.  Other  moUusks  burrow  deep  in  the  mud, 
many  prefer  sandy  bottoms,  while  a  host  of  other  species  seek 
homes  upon  the  tangled  masses  of  seaweed,  living  like  arboreal 
creatures  in  the  submarine  forests.  Nearly  every  conceivable 
character  of  sea-bottom  or  shore-line  between  tides  harbors  its 
own  peculiar  types  of  molluscan  life.  There  are  some  very  curious 
genera  of  bivalves  that  bore  their  way  into  the  hardest  rock  and 


314  MARINE  INVERTEBRATES 

there  find  a  comfortable  shelter  for  life.  A  numerous  class  of 
pelagic  or  free-swimming  mollusks  supposedly  never  go  to  the 
bottom  at  all,  but  spend  the  whole  of  their  existence  on  or  near 
the  surface  of  the  sea,  always  in  open  water,  where  their  fragile 
shells  may  not  be  inj  ured  by  rough  contact  with  solid  substances. 

The  food  of  some  is  vegetable,  of  others,  animal.  The  bivalves, 
like  the  clams,  oysters,  cockles,  and  mussels,  feed  only  on  micro- 
scopic organisms.  They  create  a  current  of  water  through  their 
siphons,  or  mantle  openings,  and  then,  by  a  process  best  known  to 
themselves,  catch  and  swallow  all  the  animalcule  thus  brought 
to  their  mouths.  The  univalves  which  possess  a  siphon  are,  for 
the  most  part,  carnivorous,  and  are  often  most  voracious  crea- 
tures. They  feed  upon  any  animal  matter  they  can  find,  while  some 
of  them  are  enabled  by  means  of  a  sharply  toothed  tongue  to  bore 
through  the  solid  shells  of  other  mollusks  and  extract  the  succu- 
lent vitals  from  within.  One  energetic  little  mollusk  in  particular, 
Urosalpinx  cinerea,  is  for  this  reason  a  great  pest  upon  the  oyster- 
beds.  Univalves  not  possessed  of  a  siphon  may  generally  be 
considered  herbivorous  ]  they  pass  most  of  their  time  peacefully 
browsing  upon  algae. 

Mollusks  are  all  oviparous  or  ovoviviparous  j  that  is,  they  lay 
eggs,  or,  laying  eggs,  they  retain  them  within  their  shells  until  the 
young  are  hatched  out.  As  a  rule,  each  species  of  mollusk  has 
its  own  particular  method  of  protecting  its  eggs  from  external 
injury.  Some  construct  tough,  leathery  capsules  which  are  strung 
together  in  various  patterns.  The  egg-capsules  of  Purpura  lapil- 
lus,  resembling  little  pinkish  or  yellowish  club-shaped  stalks,  may 
frequently  be  found  in  the  crevices  of  rocks  and  under  the  rock- 
weeds.  The  egg-cases  of  Polynices  (Ltmatia)  are  most  peculiar, 
resembling  inverted  gelatine-bowls  with  the  bottom  knocked  out ; 
when  wet  they  are  semi-elastic  translucent  masses  in  which 
may  be  seen  myriads  of  eggs.  Buccinum  undatum  arranges  its 
hemispherical  egg-capsules  in  layers  one  above  the  other.  The 
number  of  eggs  so  deposited  is  often  very  great,  running  well  into 
the  thousands.  Egg-capsules  of  Fulgnr  are  leathery  coils  of 
angular  disks  adhering  by  one  edge  to  a  connecting-band  of  a 
similar  texture.     (See  Plate  I.) 


MOLLUSKS  .  315 

In  bivalves  the  eggs  are  retained  within  the  parent  shell  until 
hatched,  and  the  young,  which  then  escape  into  the  water,  are  very 
different-looking  creatures  from  the  parent.  Generally  the  young 
bivalve  is  free- swimming  and  exceedingly  lively  in  its  move- 
ments ;  sometimes  by  means  of  cilia  it  is  enabled  to  attach  itself 
to  any  passing  host,  and  thus  the  species  is  widely  disseminated. 
The  fry  soon  lose  their  embryonic  form  and  take  on  the  charac- 
teristics of  the  adult. 

The  longevity  of  mollusks  varies  greatly  with  the  species.  Some 
attain  an  age  of  from  ten  to  fifteen  years,  while  some  are  only 
annuals.  Oysters  continue  to  grow  for  four  or  five  years,  after 
which  they  may  survive  many  years  more.  In  truth,  little  is 
known  concerning  the  duration  of  life  even  of  our  better-known 
shore  species. 

In  point  of  intelligence,  moUusks  must  be  relegated  to  a  very 
low  position.  They  give  evidence  of  possessing  no  more  than  the 
most  primary  instincts,  those  of  self-preservation  and  of  repro- 
duction. There  are  some  forms  that  exercise  a  high  degree  of 
protective  mimicry.  The  highest  class  of  mollusks,  the  Cephalop- 
oda (cuttlefishes,  octopi,  etc.),  is  widely  separated  from  the  other 
classes  in  the  development  of  faculties  that  appear  to  correspond 
with  intelligence.  They  are  exceedingly  crafty  in  the  pursuit  of 
their  prey  as  well  as  in  eluding  capture. 

STRUCTURE   OF   MOLLUSKS 

Among  the  invertebrate  animals,  especially  in  the  lower  orders, 
wide  physiological  departures  from  central  or  typical  forms 
are  frequent.  It  often  happens  that  a  whole  group  or  even  sub- 
order will  differ  so  materially  in  its  general  characteristics  from 
another  group  or  suborder  belonging  to  the  same  phylum  that  the 
student  will  be  puzzled  at  first  to  understand  how  the  two  can  be 
nearly  related.  In  many  such  cases  it  is  only  when  the  essen- 
tial features  of  the  phylum  are  thoroughly  understood  that  the 
relationships  of  its  suborders  can  be  appreciated.  An  example 
of  widely  divergent  groups  within  the  same  phylum  has  already 
been  shown  in  the  JEcMnodemiata.  Who  would  at  first  suppose 
that  the  graceful  Astrophyton  could  bear  kinship  to  the  inert  holo- 


316  MARINE  INVERTEBRATES 

thurian,  or  that  Doth  of  these  have  the  closest  family  ties  with 
the  sea-urchins  ? 

The  probable  reason  for  these  startling  departures  from  a  typi- 
cal form  is  that  in  the  lower  orders  of  lif e,  where  the  organs  and 
their  functions  are  comparatively  simple,  the  laws  of  evolution 
operate  far  more  quickly  in  the  adaptation  of  an  organism  to 
environment  and  changed  conditions  of  life.  A  decided  tendency 
to  this  departure  from  the  type  is  a  feature  of  the  mollusks.  It 
would  be  difficult,  if  not  impossible,  to  give  a  general  description 
that  would  fit  both  a  common  garden-snail  and  the  common  oyster, 
yet  both  are  mollusks.  A  concise  definition  of  the  phylum  is  there- 
fore practically  impossible,  and  it  seems  here  as  if  nature  resented 
all  attempts  to  circumscribe  her  living  forms  by  rigid  rules. 

The  most  persistent  characteristic  of  the  MoUusca  is  the  posses- 
sion of  the  "  mantle,"  a  sort  of  outer  skin  which,  like  a  bag  or  sack, 
envelops  the  creature  above  and  about  the  sides,  but  is  open 
below,  permitting  the  animal  at  will  to  protrude  or  withdraw  its 
foot.  From  the  outer  surface  of  this  sheath-like  mantle,  or  fold, 
a  calcareous  shell  is  secreted.  The  modifications  of  this  mantle 
are  infinite;  indeed,  in  some  well-marked  groups  it  seems  to 
have  wholly  disappeared,  having  in  reality  become  fused  to  the 
sides  of  the  animal,  and  having  become  therefore  a  mere  outer 
skin,  and  no  longer  a  tunic  or  cloak,  as  originally  intended.  As 
already  noted,  the  mantle  does  not  always  secrete  a  shell,  a  fact 
which  again  reminds  us  that  we  cannot  give  a  good  comprehen- 
sive description  of  the  phylum  that  always  holds  true  throughout 
its  subdivisions.  The  best  that  can  be  done  is  to  give  in  general 
terms  the  characters  which  appear  in  a  majority  of  the  forms.  A 
convenient  method  of  going  about  this  is  to  create,  for  the  sake  of 
clearness,  an  ideal,  model,  or  fanciful  moUusk  and  clothe  it  with  all 
the  most  salient  molluscan  features,  and  from  such  a  basis  to  de- 
velop, as  we  go  on,  the  various  types  of  the  actual  orders  and  sub- 
orders. There  is  one  class  of  mollusks,  the  Amphmeura,  which 
conforms  reasonably  well  in  most  of  its  features  to  our  compre- 
hension of  the  schematic  mollusk.  This  class  is  sometimes  referred 
to  by  biologists  as  the  ^^ primitive"  or  "original"  mollusks,  from 
which  all  the  other  classes  have  since  been  derived ;  but  the  evolu- 


MOLLUSKS  317 

tionary  history  of  the  development  of  the  various  moUuscan  orders 
through  geological  time  does  not  seem  to  bear  out  the  fact  that  an 
'^  ideal "  mollusk,  as  we  shall  construct  him,  ever  actually  existed, 
or  that  his  prototype,  the  Anqyhineiira,  was  the  first  and  conse- 
quently the  ancestral  type  of  the  phylum.  We  must  therefore 
only  accept  this  ideal  mollusk  theoretically,  to  serve  as  a  guide 
for  the  time  being.  We  may  profitably  use  it  only  as  a  lay 
figure— a  sort  of  manikin,  which  will  introduce  us  to  the  phylum. 
After  our  introduction  we  must  forget  our  imaginary  type  and 
abandon  any  notion  we  may  have  conceived  of  the  parental  posi- 
tion of  the  Amphineura,  its  closest  imitator  in  actual  life. 

THE   IDEAL  MOLLUSK 

The  ideal  mollusk  has  a  compact,  somewhat  elongated  body, 
the  under  or  ventral  portion  of  which  is  thickened  into  a  mus- 
cular disk,  upon  which  it  creeps  along.  This  disk  is  called  the 
foot.  (Note  a  snail  thus  crawling  upon  his  '^  foot.")  The  foot  is 
rounded  or"^obtusely  pointed  posteriorlyo  Forward,  the  body  is 
slightly  narrowed  into  a  neck,  and  then  expanded  again  into  a 
head.  Upon  this  head  are  carried  two  projecting,  mobile,  fleshy 
tentacles,  one  upon  each  side,  that  superficially  resemble  two 
horns.  At  the  base  of  each  tentacle,  upon  the  inner  side,  is  an 
eye.  Just  below  and  between  the  tentacles  is  a  small  horizontal 
slit,— the  mouth,— the  lips  being  slightly  thickened.  The  visceral 
portion  of  the  animal  is  above  the  foot,  or  dorsal  to  it,  and  ex- 
tends the  whole  length  of  the  animal  from  the  mouth  to  the 
excretory  opening,  the  latter  being  situated  posteriorly.  The 
visceral  cavity  is  inclosed  above  by  a  thin  skin ;  indeed,  it  is  but 
the  great  thickening  of  this  skin  below  that  constitutes  the  foot. 

The  digestive  tract,  beginning  at  the  mouth,  opens  immediately 
into  a  muscular  throat,  which  is  called  the  buccal  mass.  Within 
the  buccal  mass  there  is  a  long,  fleshy  ribbon  that  bears  upon  its 
upper  surface  numerous  rows  of  sharp  teeth ;  these  rows  of  teeth 
ran  crossways  on  the  ribbon,  each  row  containing  more  or  less 
prominent  median  teeth,  with  several  laterals  upon  each  side,  and 
with  marginal  teeth  on  each  side  of  the  laterals.  This  is  called 
the  radula,  and  is  used  for  tearing  or  rasping  the  food.     When 


318 


MARINE  INVERTEBRATES 


Ideal  or  schematic  mollusk. 

1,  dorsal  view:  h,  head;  t,  cephalic  tentacle;  sh.,  shell  covering  visceral  mass;  b.m.,  outline  of 
body -mass ;  r.  m.  e.,  edge  of  mantle ;  c.t,  ctenidia,  or  gills  ;  g.  a.,  generative  apertures  ;  r.  e.,  renal 
openings  ;  e.  o.,  excretory  opening ;  /,  posterior  portion  of  foot ;  o.  e.  m.,  edge  of  shell. 

2,  ventral  view :  7i,  head;  t,  tentacle;  m,  mouth;  &,  outline  of  body;  e.  m.,  edge  of  mantle;  s./., 
lower  surface  of  foot ;  c.  t.,  ctenidia,  or  gills  ;   /,  posterior  portion  of  foot. 

3,  horizontal  section,  showing  heart,  nephridia,  and  gonads  :  m,  mouth  ;  o,  esophagiis ;  g,  gonad ; 
p,  pericardium ;  n,  nephridium,  or  renal  organ;  v,  ventricle ;  a,  auricles ;  g',  gonad  aperture ;  n', 
renal  opening ;  e,  excretory  opening ;  /,  posterior  portion  of  foot. 

4,  vertical  median  section:  m,  mouth;  h.m.,  buccal  mass;  I,  liver;  d.a.,  digestive  tract;  q, 
gonad;  /,  foot ;  q.o.,  gonad  aperture,  or  opening  of  oviduct;  r.  o.,  renal  opening  ;  e.o.,  end  of  diges- 
tive tract,  excretory  opening ;  n,  mantle;  r,  nephridium,  or  renal  organ;  o.f.,  recurved  portion  of 
mantle ;  sh. ,  shell ;  v,  ventricle  ;  p,  pericardium. 


MOLLUSKS  319 

not  in  use  it  lies  coiled  up  within  the  buccal  mass.  Beyond  the 
buccal  mass,  food  passes  into  the  esophagus,  which  widens  out 
into  a  muscular  pouch  or  stomach;  this  may  also  be  provided 
with  chitinous  teeth  or  hard  knobs  or  plates  for  the  purpose  of 
further  triturating  the  food.  Above  and  partially  surrounding 
the  stomach  is  a  large  reddish  or  brownish  liver,  which  furnishes 
to  the  alimentary  canal  the  digestive  juices.  From  the  stomach 
the  intestine  leads  to  the  terminal  anal  opening.  There  are  two 
organs,  serving  the  function  of  kidneys,  placed  dorsally  one  upon 
each  side  of  the  body  (nepJiridia).  A  heart  lies  within  the  median 
line  of  the  body,  and  consists  of  a  ventricle  and  two  lateral  auri- 
cles. The  vascular  system  is  almost  entirely  closed ;  only  in  so  far 
as  it  is  partially  open  does  it  essentially  differ  from  that  of  higher 
groups;  the  blood  is  whitish  or  light  bluish,  and  receives  its 
oxygenation  in  the  gills  or  along  the  free  mantle  surface,  through 
which  it  courses  in  exceedingly  thin  capillaries.  In  this  manner 
respiration  is  carried  on  to  some  extent  throughout  the  whole 
outer  surface  of  the  body.  There  are  two  IrancMce  (gills).  These 
have  the  appearance  of  small  feathers  and  are  placed  upon  each 
side  of  the  animal  posteriorly;  they  project  slightly.  Spread 
over  the  top  of  this  animal,  fitting  it  perfectly,  is  a  thin  fleshy 
covering  attached  to  its  dorsal  portion  like  a  skin,  but  hanging 
free,  like  a  flap,  over  the  sides,  the  head,  and  the  posterior  end  of 
the  animal.  Upon  the  sides  it  may  just  cover  the  tips  of  the  bran- 
chiaB,  but  in  front  the  head  is  seen  to  project  from  under  it. 
The  loose-hanging  portion  of  this  sac-like  covering  is  somewhat 
thickened,  and  perhaps  recurved  upward  upon  itself.  Upon  the 
edge  of  this  flap  all  the  way  around  may  occur  a  row  of  cilia,  or 
tentacular  processes.  This  cloak-like  covering  is  called  the  mantle, 
and,  as  already  noted,  is  the  most  peculiar  and  persistent  charac- 
teristic of  the  MoUitsca.  The  '^  cavity  "  formed  between  the  loose- 
hanging  portion  of  the  mantle  and  the  sides  of  the  foot  is  called 
the  mantle  cavity,  and  contains  posteriorly  the  gills,  or  branch!^. 
From  the  outer  surface  of  this  mantle  a  calcareous  secretion  takes 
place,  forming  a  shell,  which,  in  our  ideal  mollusk,  will  be  shaped 
in  conformity  with  the  surface  outlines  of  the  mantle,  oblong  and 
convex  above.     Over  the  lower  portion  of  the  shell  the  edge  of 


320  MARINE   INVERTEBRATES 

the  mantle  recurves.  When  the  creature  is  disturbed  or  is  at 
complete  rest  it  may  withdraw  that  portion  of  the  mantle  which 
protrudes  from  below  the  shell  entirely  within  the  edge  of  the 
shell,  so  that  the  '^  soft  parts  "  may  be  wholly  covered,  and  thus 
protected  from  harm.  In  such  a  state  of  rest  nothing  may  be 
seen  from  above  but  a  shell.  The  entire  upper  surface  of  the 
mantle  is  firmly  attached  to  the  under  or  inner  side  of  the  shell, 
except  the  mantle  margin,  this  being  free. 

The  nervous  system  consists  of  a  cir  cum  esophageal  ring  of 
nerve-cells,  with  two  cords  passing  along  the  digestive  tract  to 
the  posterior  end  of  the  animal.  In  the  head  and  above  the 
buccal  mass  are  several  series  of  nerve-ganglia.  These  also  com- 
municate with  the  posterior  portion  of  the  animal  through  two 
parallel  cords  which  pass  along  its  ventral  side.  From  these 
four  principal  branches,  which  traverse  the  entire  length  of  the 
creature,  minor  nerve-cords  are  thrown  off  to  the  tentacles,  the 
foot,  the  branchiae,  and  the  various  organs  of  the  viscera.  The 
sexes  are  separate. 

Reviewing  our  '^  typical  moUusk,"  we  find  that  it  is  bilaterally 
symmetrical— that  is,  uniform  upon  both  sides  of  a  median  line 
from  mouth  to  excretory  opening ;  is  unsegmented ;  has  the  ven- 
tral surface  thickened  into  a  creeping  foot  or  disk ;  and  is  pos- 
sessed of  a  head  with  tentacular  processes,  a  radula,  lateral 
branchiae,  a  heart  with  a  ventricle  and  two  auricles,  a  well-devel- 
oped mantle,  and  a  shell. 

If  the  reader  can  learn  these  few  details  of  organization  he 
knows  the  structure  of  a  moUusk.  In  turning  to  the  actual 
living  forms  he  will  find  merely  modifications  (though  sometimes 
confusing  ones)  of  these  various  parts. 

CLASSIFICATION 

The  Mollusca  are  divided  into  five  great  classes :  Amphineura, 
Gasteropoda,  Scapho2)oda,  Felecypoda,  and  Cephalopoda.  These 
names,  it  will  be  noticed,  with  the  exception  of  the  first,  all  refer 
to  the  foot,  the  modifications  of  the  foot  being  selected  as  the  basis 
of  the  first  great  divisions  of  the  phylum.  The  Gasteropoda  crawl 
upon  the  thickened  ventral  surface  of  their  bodies  (already  re- 


MOLLUSKS  321 

ferred  to  as  the  foot),  as  the  common  garden- snail,  the  peri- 
winkles, and  in  general  all  those  moUusks  which  have  a  spirally 
coiled  shell.  The  SccqjJwjwda  have  a  long,  worm-like  foot,  with 
which  they  burrow  in  the  sand  or  mnd.  Their  shells  are  like 
miniature  elephant-tusks,  but  are  open  at  both  ends.  The  Pele- 
cypoda  have  a  more  or  less  club-shaped  foot,  utilized,  in  the  many 
families,  for  a  great  variety  of  purposes.  They  are  always  in- 
closed in  a  bivalve  shell.  Familiar  examples  are  the  oysters, 
the  clams,  mussels,  etc.  The  Cephalopoda  have  the  foot  modified 
into  a  number  ot  arms,  which  encircle  the  head  or  the  mouth. 
They  are  the  cuttlefishes,  the  octopi,  squids,  etc. 

CLASS   AMPHINEURA 

ORDER  POLYPLACOPHORA 

The  AmpMneura,  as  already  observed,  approach  most  closely 
to  the  ideal  mollusk  just  described.  They  are  bilaterally  sym- 
metrical. This  fact  is  so  important  that  it  constitutes  them  a 
class,  notwithstanding  the  fact  that  in  respect  to  the  foot  (the 
basis  of  division  into  classes)  they  would  be  included  with  the 
Gasteropoda,  for  (barring  some  exceptional  instances)  they  creep 
along  upon  a  foot  quite  as  our  ideal  mollusk  would,  and  as  the 
Gasteropoda  do.  The  head  carries  no  tentacles,  thus  essentially 
differing  in  this  respect  from  the  ideal  form.  The  mantle  is 
extended  down  in  front,  completely  covering  the  head.  The 
branchiaB  are  confined  to  a  few  pairs  of  ctenidia,  or  plume-like 
gills,  within  the  mantle  groove  or  cavity,  and  are  arranged  upon 
each  side  of  the  excretory  opening  like  small  feathers. 

There  are  two  orders  of  the  AmpMneura,  the  Polyplacopliora 
and  the  Aplacopliora  (or  Solenogastres),  the  one  name  mean- 
ing ''bearing  many  plates,"  and  the  other  ''without  plates," 
the  word  "  plate  "  in  this  sense  being  synonymous  with  "  shell." 
The  shell  of  the  first  order  consists  of  eight  calcareous  disks 
arranged  in  a  longitudinal  row  along  the  back  or  dorsal  side  of 
the  animal,  which  overlap  like  shingles  on  a  roof  and  admit  of 
great  variation  of  form  in  the  various  families. 

21 


322 


MARINE  INVERTEBRATES 


Chiton  spinosus,  dorsal  view. 


jno 


It  will  be  observed  from  the  examples  given  that  the  shell  plates 
do  not  entirely  cover  the  mantle,  but  that  a  considerable  portion 
of  the  upper  mantle  surface  is  left  exposed  along  the  side  of  the 

animal.  This  exposed  portion  of  the 
mantle  is  called  the  girdle.  It  is  always 
very  much  thickened  and  is  often  ex- 
ceedingly tough.  In  some  species  it  is 
covered  by  a  great  number  of  calcare- 
ous spicules  or  granules  which  are  em- 
bedded in  the  leathery  mantle  tissue. 
Strangely  enough,  the  Chitonidce  (a  large 
family  of  the  Polyplacophora)  possess  a 
great  number  of  eyes  scattered  over  the 
shell  plates  like  minute  dots. 

The  members  of  this  order  are  to  be 
found  in  all  parts  of  the  world,  but 
their  greatest  development  is  upon  the 
west  coast  of  America.  In  California 
the  student  of  marine  life  has  a  splen- 
did opportunity  to  examine  the  chitons. 
They  are  generally  to  be  found  adhering 
to  the  under  surface  of  stones  about  low- 
tide  mark.  They  are  very  sluggish  in 
their  movements  and  may  readily  be  re- 
moved from  their  resting-places  by  sud- 
denly thrusting  a  knife-blade  under  the 
foot  and  prying  them  off.  When  thus 
detached  they  have  a  habit  of  rolling  up 
up  into  a  ball  and  so  remaining  indefi- 
nitely; to  prevent  this  they  should  be 
placed  at  once  in  a  jar  of  sea-water, 
where  they  will  resume  their  natural 
position.  For  preservation  as  cabinet 
specimens,  chitons  should  be  tied  down 
between  two  boards  or  flat  substances,  to  hold  them  firmly  ex- 
tended until  dried;  otherwise  they  are  apt  to  contract  out  of 
shape. 

Six  or  eight   species  are  exceedingly  common  upon  the  west 


Tnant 


cten 


CCTL 


Chiton,  ventral  view :  an,  anus ; 
cten,  ctenldia;  ft,  foot;  mant,  man- 
tle-edge ;  mo,  mouth. 


MOLLUSKS  323 

coast.  The  collector  who  has  successfully  taken  a  number  of 
these  will  not  fail  to  note  the  varying  degrees  of  width  of  the 
girdle  in  the  different  species.  In  some 
cases  the  girdle  partially  covers  the  over- 
lapping shell  plates.  The  largest  of  all 
the  chitons  inhabits  the  California  shores 
and  is  known  as  Cryptochiton  stelleri. 

It  measures  fully  six  inches  in  length  and  ^,^.^^^  ,^,^j,,^  Chiton  apMatm. 
three  in  width.  In  Cryptocliiton  the  gir- 
dle is  continued  over  the  sheh  plates  as  a  tough,  gritty,  brownish 
covering.  The  shell  plates  are  white,  and,  as  detached  pieces,  are 
frequently  to  be  found  cast  up  upon  the  California  beaches,  where, 
from  their  curious  shape,  they  are  often  referred  to  as  ''  butterfly- 
shells." 

On  the  east  coast  of  America  there  are  comparatively  few 
species,  and  these  are  all  small  and  inconspicuous.  The  three 
commonest  ones  are  Chiton  ruber,  C.  alhus,  and  C.  apiculatus. 
They  may  readily  be  found  on  stones  or  dead  shells  fished  up 
from  below  low-tide  mark,  or  in  rock-pools  left  by  the  receding 
tide. 

ORDER  APLACOPHORA 

This  second  order  of  the  Ampliineura  is  entirely  destitute  of 
the  shell  plates  characteristic  of  the  first.  The  outer  mantle  sur- 
face, however,  develops  a  number  of  calcareous  granules  which 
correspond  to  a  shell.  The  Aplacophora  are  symmetrical,  having 
the  mouth  and  the  excretory  opening  at  the  anterior  and  posterior 
ends  respectively.  The  foot  is  greatly  modified,  being  narrowed 
at  times  to  a  mere  slit  along  the  ventral  surface.  Some  of  them 
have  long,  worm-like  bodies.  This  is  no  doubt  a  very  primitive 
form  of  moUusk,  or,  if  not  a  primitive  form,  it  has  greatly  degen- 
erated from  some  higher  type.  They  are  supposed  to  be  com- 
mensal in  habit  and  live  in  the  deeper  water  offshore. 

The  Aplacophora  are  not  littoral  animals,  and  it  is  extremely 
unlikely  that  one  will  ever  encounter  them  upon  the  beach,  un- 
less, possibly,  after  the  severest  of  storms.  We  may  therefore 
leave  them  with  this  mere  mention  and  proceed  to  the  second 
class  of  moUusks,  the  Gasteropoda. 


TABLE  SHOWING  THE  CLASSIFICATION  OF  THE  GASTEROPODS 
AND  SCAPHOPODS  DESCRIBED  IN  THIS  CHAPTER 

Phylum 

MOLLTJSGA 


Class 
GASTEROPODA 

Order  OPISTHOBKANCHIATA 


Suborders     Families 

TECTIBRANCHIATA 


APLYSIID^ 
NUDIBRANCHIATA 

DENDRONOTID^ 

^OLIDID^ 

DORIDID^ 


Genera 


BULLiD^      Bulla 


Aplysia 

Dendronotus 

jEolis 

Doris 


Species 


B,  (Haminea)  solitaria 
B,  occidentalis 
B,  nebulosa 

A,  Wilcoxii 

D,  arhorescens 
JEJ.  papulosa 

B,  hilamellata 


Order  PROSOBRANCHIATA 


DIATOGARSIA 


ACM^ID^ 


FISSURELLID^ 


Acmwa 


,  Lottia 


Fissurella 


^Lucapina 


HALIOTID^      Haliotis 


A,  testudinalis 

A.  testudinalis f 
Var.  alveus 

^A.  mitra 

A,  patina 

L,  gigantea 
f  F,  alternata 
I  F.  barbadensis 
V  J^.  (Glyphis)  aspersa 

L,  cremdata 
C  IT.  splendens 
<  H.  rufescens 
I H,  cracherodii 


324 


GASTEROPODS 


325 


Suborders     Families  Genera 

Margarita 


TROCHIDJE 


Calliostoma 


Chlorostoma 

Trochisciis 
,  Livona 


TURBiNiD^      Turbo 


CNerita 


NERITID^ 


\ 


Neritina 


MONOTOCARDIA 

JANTHINID^    JantMna 
SCALID^      Scala 


NATICID^ 


CAPULID^ 


Polynices 

Natica 
Sigaretus 

{Crepidula 
Crucibulum 


LiTTORiNiD^  \  lAttorina 


Species 
M,  cinerea 
M,  helicina 
M,  undulata 
C,  occidentale 
C,  jujubinum 
C.  annulatum 
C  canaliculatufn 
-C.  costatuni 
C,  funebrale 
C,  brunneum 
T,  norrisi 
L.  pica 
T,  castaneus 
T,  castaneus, 

Var.  crenulatus 
N.  peleronta 
W,  tessellata 
N.  versicolor 
N,  reclivata 
N,  viridis 

J,  fragilis 
'S.  lineata 
S,  tnultistriata 
S,  groenlandica 
^S,  angulata 
P.  (Lunatia)  heros 
-P.  (Lunatia)  triseriata 
P.  (Lunatia)  lewisii 
P.  (Neverita)  duplicata 
P.  (Keverita)  recluziana 
N.  clausa 
iV.  canrena 
S,  perspectivus 
C,  fornicata 
I  C.  plana 
C,  aculeata 
C  striatum 
C,  spinosum 
L,  litorea 
L,  rudis 
L,  palliata 
L,  irrorata 
L,  angulifera 
L,  scutulata 
,L.  planaxis 


326 


MARINE  INVERTEBRATES 


Families  Genera 

C  Lacuna 


Cerithiiim 


CERITHIID^ 


Bittiufn 
Cerithidea 
VERMETiD^       Vermicularia 
STROMBiD^      Strombus 

Cyprcea 


CYPE^ID^ 


DOLIID^ 


Trivia 


S  Dolium 
(  Pyrula 


CASSiDiD^      Cassis 

I  Mureoc 

I  Trophon 
\  Urosalpinx 
MURiciD^     j  Eupleura 

Subfamily    ( pteronotus 
Murieinse 

Ocinehra 

Cerostoma 


Subfamily 
Purpurinse 


.Purpura 


Monoceras 
Chorus 


Species 
X.  vincta 
T,  muricatus 
T.  nodulosus 
C.  fioridanum 
C.  muscarum 
C.  minimum 

B,  nigrum 

C,  scalariformis 
C.  sacrata 

V,  spirata 
S.  pugilis 
S.  gigas 
C,  exanthema 
C,  spurca 

C,  spadacea 
T,  pediculus 

T,  quadripunctata 
T,  californica 
■T,  solandri 

D,  galea 
D»  perdidc 

jP.  papyratia 
C.  tuberosa 
C,  cameo 
C,  testiculus 
.C,  inflata 
M.  rufus 
M,  pomum 
T,  clathratus 
IT,  cinerea 

E,  caudata 
JP,  festivus 
O,  poulsoni 
O,  lurida 

O,  interfossa 
C,  nuttallii 
C.  foliatiun 
P,  lapillus 
P,  patula 
P,  hcemastoma 
P,  crispata 
P,  lima 
P,  saxicola 
M.  lapilloides 
M,  engonatum 
C,  belcheri 


GASTEROPODS 


327 


Families 


Genera 


COLUMBELLID^      Columbella" 


NASSiD^      Nassa 


BUCCINID^ 


TURBINELLID^ 


FASCIOLARIID^ 

VOLUTID^ 
MARGINELLID^ 

OLIVID^ 

CONID^ 
CANCELLARIID^ 


Buccinum 
Chrysodomus 

SipJio 

Siphonalia 
Tritonidea 

Melongeua 

Fasciolaria 

Voluta 

Marginellci 

Oliva 

Olivella 

Conus 
Cancellaria 


Species 

C,  mercatoria 

C  (Anachis)  avara 

C,  similis 

C.  (Astyris)  lunata 

C  (Amphissa)  corrugata 

C,  (Astyris)  gaiisapata 
'^,  trivittata 

W,  obsoleta 

N,  vibeoc 

W,  fossata 

N.  perpinguis 

JV.  tegula 
,N,  mendica 

jB.  undatum 

C,  decemcostatus 

S.  Stinipsoni 

S,  pygmceus 

S,  kellettii 

T,  tincta 
'F.  carica 

F,  canaliculata 

F,  perversa 
-F,  pyrum 

M,  corona 

F,  gigantea 
I  F,  tulipa 

F,  distans 

V,  junonia 

M,  apicina 

O,  literata 

O.  mutica 

O,  hiplicata 

O.  hoetica 

C  floridanus 

C  pealii 

C.  reticulata 


DENTALID^ 


Class 
SCAPHOPODA 

I  Dentalium 


I 


Entalis 


D,  dentale 
D.  pretiosum 

D.  hexagomt/m 

E,  striolata 


^ 


CLASS  GASTEROPODA 

THE  class  Gasteropoda  is  the  largest  and  most  compreliensive 
subdivision  of  the  MoUusca,  and  within  its  wide  range  of 
families  many  differing  details  of  organization  are  to  be  found. 
As  a  class  it  possesses  all  the  most  characteristic  features  of  the 
phylum,  though  it  is  frequently  modified  in  a  high  degree.  This 
class  includes  all  the  univalve  mollusks  (except  Nautilus  and 
Dentalia),  such,  as  the  snails,  the  whelks,  and  the  host  of  spirally 
coiled  land,  fresh- water,  and  marine  shells. 

The  gasteropod  foot  is,  as  has  been  remarked,  primarily  the 
same  as  in  our  schematic  moUusk— a  flat,  muscular  disk  caused 
by  the  thickening  of  the  ventral  body-surface.  The  neck,  head, 
and  tentacles  are  also  quite  the  same,  but  considerable  modifica- 
tion of  these  organs  will  be  found  when  we  come  to  examine 
some  specimens.  The  mantle  is  always  present,  except  in  the 
nudibranch  or  non-shell-bearing  forms ;  but  in  few  of  the  Gas- 
teropoda is  the  mantle  so  regularly  simple  as  in  our  ideal  mollusk. 

Perhaps  the  most  striking  feature  of  the  Gasteropoda,  and  one 
that  will  at  first  surprise  him  who  has  in  mind  the  simple  struc- 
ture of  the  ideal  mollusk,  is  the  fact  that  they  are  always  asym- 
metrical—that is  to  say,  a  median  line  drawn  longitudinally 
through  a  gasteropod  will  not  divide  it  into  halves  of  similar 
anatomical  structure. 

The  quality  of  symmetry  is  an  important  one  throughout  the 
lower  orders  of  animal  life.  In  nearly  all  phyletic  or  class  de- 
scriptions the  word  '^ symmetry"  occurs,  and  its  exact  meaning 
must  be  understood.  Take,  for  example,  a  human  being ;  a  median 
line  drawn  vertically  would  divide  him  into  two  similar  halves — 
upon  each  side  would  be  an  eye,  an  arm,  a  leg,  etc.,  of  similar 
shape  and  construction.     So  far  at  least  as  the  external  features 

328 


GASTEROPODS  329 

go,  man  is  then  a  symmetrical  creature ;  likewise  the  vertebrates 
in  general.  Cases  of  actual  symmetry  are  found  in  the  lobsters 
and  crabs  and  in  the  segmented  worms.  It  is  usual  in  describing 
mollusks  broadly  and  in  general  terms  to  call  them  symmetrical 
animals,  yet  here  is  the  largest  class  within  the  phylum,  whose 
representatives  are  none  of  them  symmetrical.  In  the  Gasteropoda 
the  mouth  is  anteriorly  placed  in  the  head,  just  as  in  the  ideal 
form,  but  the  digestive  tract,  after  traversing  the  visceral  cavity 
in  the  usual  fashion,  suddenly  turns  forward  and  terminates 
in  an  excretory  opening  either  on  the  right  or  on  the  left 
side  of  the  animal,  just  back  of  the  head.  The  various  other  ori- 
fices for  the  genital  and  renal  glands  are  also  placed  in  this 
unexpected  anterior  position.  The  gills,  or  branchise,  are  to  be 
found  upon  one  side  only,  forward  of  the  *  heart,  and  differ 
somewhat  in  appearance  from  the  plume-like  processes  of  the 
Amphineura. 

What,  then,  has  become  of  the  corresponding  gill  we  should  ex- 
pect to  find  on  the  other  side?  The  symmetrical  shape  of  the 
foot  is  not  in  the  least  altered,  but  what  has  happened  to  cause 
this  distortion  of  the  visceral  portion  of  the  animal?  And, 
finally,  will  this  torsion  of  the  body  of  the  snail  perhaps  account 
for  the  spiral  nature  of  the  shell  ? 

An  evolutionary  process  is  supposed  to  have  taken  place  in 
mollusks,  which,  if  real,  would  no  doubt  account  for  these  curious 
conditions  of  torsion  in  the  Gasteropoda;  but  the  theory  upon 
which  this  process  is  based  is  altogether  speculative,  and  is  not 
fully  sustained  by  the  facts  in  the  case.  Originally  all  mollusks 
are  presumed  to  have  been  symmetrical,  and  are  assumed  to  have 
resembled  very  much  in  form  the  schematic  creature  we  have 
already  described.  Now,  for  some  reason,  certain  of  the  primitive 
mollusks,  but  not  all  of  them,  began  to  develop  a  larger  visceral 
mass,  which,  continuing  to  enlarge  throughout  many  generations, 
began  finally  to  protrude  above  and  form  a  hump  on  the  dorsal 
side  of  the  animal.  This  hump,  containing  the  liver,  a  portion  of 
the  intestines,  and  the  generative  glands,  as  it  increased  in  bulk 
became  so  much  elevated  that  it  could  no  longer  maintain  itself 
in  an  erect  position  over  the  body,  but,  impelled  by  its  own 


330  MARINE  INVERTEBRATES 

weight,  began  to  sag  over  to  one  side.  Such  a  process  would  of 
course  tend  to  twist  the  digestive  tract  and  bring  the  excretory 
opening  constantly  farther  forward  on  one  side.  At  the  same 
time,  this  process  would  necessarily  interfere,  by  the  weight  of 
the  overhanging  viscera  and  the  sheU  covering  the  mass,  with  the 
development  of  the  branchiae  lying  upon  that  side  and  now  crowded 
under  the  visceral  mass.  Thus,  according  to  this  theory,  this 
process  has  continued  until,  in  the  modern  gasteropod,  the  diges- 
tive tract  has  been  bent  upon  itself  and  twisted  from  a  straight 
course  into  a  curve  of  almost  180°,  bringing  the  excretory 
opening  near  or  just  over  the  head,  where  it  empties  into  the 
mantle  cavity;  while  the  original  right  gill,  by  the  same  riiove- 
ment,  has  been  brought  to  a  position  on  the  left  side  of  the 
head,  forward  of  the  heart,  the  original  left  gill  having  been 
crowded  out,  eventually  to  atrophy  and  disappear.  The  same 
torsion  is  found  in  the  nerve-cords ;  the  heart,  situated  at  about 
the  pivotal  position  of  this  twisting  process,  has  turned  about 
upon  itself,  leaving  an  auricle  in  front  of  the  ventricle,  one 
auricle,  like  one  of  the  gills,  having  been  lost.  The  mantle  por- 
tion covering  the  visceral  hump  naturally  continued  to  secrete  its 
shell,  though  always  in  conformity  with  the  change,  the  result 
being  the  familiar  spiral  form  of  the  usual  gasteropod  shell. 

This  theory  may  not  be  satisfactory,  but  the  asymmetry  of 
gasteropods  is  a  problem  to  be  solved,  and  a  more  interesting 
line  of  biological  investigation  could  not  be  found. 

Let  us  now  take  a  good  example  of  a  gasteropod  and  locate  its 
various  organs ;  at  the  same  time  we  may  use  the  occasion  to 
refer  to  more  important  modifications  of  these  organs  which  will 
be  encountered  later  in  the  various  genera.  The  most  available 
gasteropod  on  the  east  coast  of  the  United  States  for  this 
purpose  is  Fiilgur,  both  on  account  of  its  large  size  and  its 
abundance.  Biiccinum  may  be  used  if  the  student  is  north  of 
Cape  Cod  and  therefore  unable  to  secure  a  good  living  specimen 
of  Fiilgur;  the  anatomical  differences  between  the  two  are  slight. 

Note  the  siphon  protruding  forward  from  a  notch  in  the  shell. 
This  consists  merely  in  an  elongation  of  a  fold  of  the  mantle, 
which  is  held  in  a  manner  to  constitute  a  tube,  through  which 


GASTEROPODS 


331 


-ai 


Buccinum  undatum  :  si,  siphon. 


the  animal  draws  in  water  to  supply  the  gills,  lying  just  back 
of  the  siphon  and  concealed  under  the  mantle  in  the  cavity 
already  spoken  of  as  the  mantle  cavity.  With  the  exception  of 
that  portion  of  the  mantle  which  constitutes  the  siphon,  no  part 
of  its  margin,  it  will  be  observed,  can  be  seen,  the  edge  of  the 
shell  completely  hiding  it  from  view. 

In  some  genera  the  siphon  is  exceedingly  long— in  fact,  longer 
than  the  body  of  the  animal.  In  these  cases  the  moUusk  is 
generally  fond  of  burying 
itself  in  the  sand  and  main- 
taining communication  with 
the  world  above  only  by 
means  of  this  long,  fleshy 
tube.  In  some  genera  the 
siphon  is  protected  by  an 
elongation  of  the  shell,  as  in 
Fasciolaria  (Plate  LXXVI). 
An  extreme  example  of  this  is  given  in  the  figure  on  page  343, 
which  represents  a  species  of  Murex,  where  the  siphon  is  not  only 
protected  by  the  shell,  but  the  shell  itself  is  further  protected  by 
the  double  row  of  sharp  spines  with  which  it  is  beset. 

There  are  some  genera  which  possess  no  siphons  at  all,  in  all 
of  which  cases  there  is  no  notch  in  the  shell  opening,  the  aperture 
being  round,  as  in  Natica  an*d  in  Littorina  (pages  368,  371).  The 
moUusks  of  this  type  make  a  fold  in  the  forward  part  of  the 
mantle  which  serves  as  a  siphon.  Such  a  muscular  folding  in 
the  mantle  would  be  technically  called  a  functional  siplion. 

On  the  posterior  dorsal  side  of  the  foot  is  attached  a  horny 
plate,  of  concentric  structure  about  a  central  or  subcentral 
point  or  nucleus.  This  is  called  the  operculum^  and  serves 
to  close  the  entrance  of  the  shell  when  the  animal  is  withdrawn, 
the  object  no  doubt  being  protective.  The  opercula  vary  to  a 
great  extent  in  the  different  genera ;  in  some  cases  they  are  cal- 
careous, in  others  cartilaginous.  When  the  aperture  of  the  shell 
is  very  large  it  often  happens  that  the  operculum  does  not  entirely 
close  the  opening,  as  in  Fulgur,  but  in  Buccinum  it  is  a  close  fit. 
The  operculum  is  entirely  wanting  in  the  Fulmonata,  one  of  the 


332 


MARINE  INVERTEBRATES 


large  orders  of  the  Gasteropoda.     The  figures  represent  some  of 
the  commoDer  types  of  opercula. 

The  opercula  have  been  utilized  a  great  deal  in  the  classification 


Various  forms  of  opercula. 


Turho 
(  Sarmaticus). 


Turho 
(  Callopoma). 


Livona. 


AmpuUaria. 


Natica. 


of  the  Gasteropoda,  and  especially  in  some  groups  that  have 
become  terrestrial  in  habit.  Often,  when  shell- characters  utterly 
fail  to  give  a  clue  to  the  proper  generic  position  of  a  new  or  rare 
mollusk,  the  operculum  may  be  relied  upon  to  indicate  it. 


Various  forms  of  opercula. 
Pyrula.       Purpura.        Littorina.       Aulopoma.        Torinia.       Neritopsis.        Strombus.        Conns. 


TENTACLES 

Two  tentacles  project  like  fleshy  horns  from  the  sides  of  the 
head.  These  are  not  retractile,  as  in  the  land-snails,  and  their 
ofB.ce  appears  to  be  that  of  sensory  organs.  In  both  Fulgur  and 
Buccimim  the  tentacles  are  comparatively  short  and  stout,  and  have 
expanded  bases ;  in  many  other  genera  they  are  long  and  slender. 
Almost  without  exception  the  Gasteropoda  possess  tentacles. 


GASTSROPODS  333 


EYES 


In  Fulgur  the  eyes  are  situated  near  the  bases  and  npon  the 
outer  sides  of  the  tentacles  j  in  Buccinuni  they  are  extremely  small 
and  are  mounted  about  midway  between  the  bases  and  the  tips  of 
the  tentacles.  This  is  the  usual  position  for  the  eyes  in  the 
marine  Gasteropoda.  Only  in  the  pulmonates,  or  land-snails,  are 
the  eyes  placed  at  the  summit  of  the  tentacles.  Sight  does  not 
appear  to  be  a  very  important  sense  in  the  gasteropods,  although 
the  eye  in  some  instances  becomes  a  highly  developed  organ.  A 
number  of  forms  that  have  the  habit  of  burrowing  deep  into  the 
sand  or  mud  are  quite  destitute  of  visual  organs,  and  certain 
cave-dwelling  land-shells  have  entirely  lost  the  sense  of  vision. 

MOUTH  AND   PROBOSCIS 

The  mouth  will  easily  be  seen  in  both  Fulgur  and  Buccinum. 
It  is  a  small  slit  with  slightly  thickened,  fleshy  lips,  and  is  placed 
on  the  lower  forward  portion  of  the  head.  In  the  case  of  both 
of  these  genera  the  mouth  is  situated  at  the  end  of  a  proboscis. 
It  will  be  noted  that  Fulgur  has  a  comparatively  long  and  stout 
proboscis,  or  snout,  which  is  not  retractile.  Buccinum  has  a  smaller 
one.  It  is  fairly  safe  to  assume  that  all  gasteropods  that  possess 
a  proboscis  are  carnivorous.  This  organ  is  greatly  developed  in 
some  genera,  where  it  actually  exceeds  in  length  the  rest  of  the 
animal.  In  such  instances,  no  doubt,  the  creature  is  enabled  to 
reach  the  interior  portions  of  the  shells  of  its  victims  and  to 
devour  every  vestige  of  their  flesh,  for  the  mouth  is  most  con- 
veniently placed  just  at  the  end  of  this  long,  trunk-like  organ. 
The  genera  which  have  no  proboscis  are,  almost  without  excep- 
tion, vegetable  feeders. 

We  must  now  remove  the  animal  from  its  shell.  It  is  well  to 
boil  it  first,  for  this  does  away  with  the  annoying  mucous  secre- 
tion that  is  freely  exuded  by  glands  in  the  foot  when  the  creature 
is  roughly  handled.  Alcoholic  specimens  are  apt  to  be  much 
contracted  and  hardened,  and  are  therefore  less  satisfactory  as 
subjects  for  anatomical  study.     If  it  is  not  convenient  to  boil  the 


334  MARINE  INVERTEBRATES 

specimen,  break  away  the  shell  with  a  hammer,  using  care  not  to 
lacerate  the  soft,  fleshy  portion  within  j  when  this  is  accomplished, 
wash  the  animal  carefully  to  remove  the  slimy  exudation.  Note 
the  ''  visceral  hump,"  which  is  spiral,  and  which  formerly  occu- 
pied the  upper- whorl  portion  of  the  shell.  The  thin  skin  covering 
it  is  the  mantle,  which  below  is  greatly  thickened  and  free,  lying 
about  the  foot  like  a  heavy  fleshy  flap. 

MANTLE 

The  mantle-edge  in  both  of  these  examples  is  simple ;  that  is  to 
say,  it  possesses  no  fringe  of  tentacles,  nor  is  it  supplemented  by 
extra  processes,  characters  which  mark  many  genera  of  marine 
Oasteropoda.  In  Fulgiir  and  Buccinum  the  mantle-edge  does  not 
protrude  below  the  edge  of  the  shell ;  but  in  many  genera,  especially 
those  which  possess  smooth,  glossy  shells,  like  the  cowries  (Gyprcea) 
and  the  graceful  Oliva,  the  mantle  is  proportionately  very  much 
larger.  In  these  two  genera,  when  the  animal  is  extended,  as  in 
crawling  about  the  sand,  the  mantle  curves  upward  and  incloses  a 
large  portion  of  the  shell  itself.  Indeed,  in  some  genera  the  shell 
is  almost  entirely  concealed  by  this  extension  of  the  mantle  (Siga- 
retus,  l^atica,  etc.). 

When  the  shell  is  removed,  the  folding  of  the  mantle  which 
constitutes  the  siphon  can  be  plainly  seen.  The  office  of  the  siphon 
has  already  been  referred  to,  also  the  fact  that  the  presence  of  a 
siphon  in  the  gasteropod  mollusk  may  always  be  determined  by 
merely  glancing  at  the  shell  alone,  for  a  notch  at  the  base  of  the 
aperture  indicates  the  place  through  which  the  siphon  passed. 
In  Buccinum  this  is  merely  a  notch,  but  in  Fulgur  the  siphonal 
canal  of  the  shell  is  much  longer.  Just  why  the  long  siphons  of 
some  moUusks  should  be  naked  and  exposed  to  danger,  while 
others  are  so  carefully  protected  by  elongated  portions  of  the 
shell,  is  a  mystery,  but  nature  is  full  of  such  contradictions. 

THE   GASTEROPOD   FOOT 

The  foot  is  long,  broad,  and  flat  on  the  under  side,  like  a 
disk.     The  variations  in  the  gasteropod  foot  are  almost  infinite. 


GASTEROPODS 


335 


In  some  of  the  species  it  is  amazingly  large  and  powerful,  as  in 
Bolynices  [Katica),  and  in  most  of  the  forms  which  live  along 
sandy  beaches.  These  are  sometimes  provided  in  front  with  a 
wedge-shaped  process  called  the  propodium,  which  serves  admir- 


s.ajj 


Si(/aretus  Icevigahis,  shoAving  excessive  development  of  the  propodium  (pr.)  and  metapodium 
(met.)  in  a  moUusk  living  in  sand  (the  shell,  Avhich  covers  only  the  liver  and  adjacent  parts,  has  been 
removed) :  I,  liver ;  s.  ap.,  aperture  of  proboscis,  here  deflected  from  the  median  line ;  t,  t,  tentacles ; 
/,  foot. 

ably  as  a  plow  to  push  aside  the  heavy  wet  sand  through  which 
the  animal  forces  its  way.  In  Nassa,  which  is  so  common  all 
along  our  coasts,  the  foot  has  two  terminal  appendages  or 
points  behind. 


m.ap'- 


Oliva  textilina  shomng  how  the  front  part  of  the  foot  (/)  is  devel- 
oped into  a  sort  offender,  the  propodium  (pr.):  e,  e,  eyes;  m.  ap.,  front  ap- 
pendage of  mantle;  m.  ap.',  hinder  appendage  of  mantle,  folded  into  the 
sutm-e  when  the  animal  is  at  rest;  si.,  siphon ;  t,  t,  tentacles. 


There  is  no  single  feature  of  moUusks  more  important  than  the 
foot,  for  upon  the  many  modifications  of  this  organ  the  various 
molluscan  classes  are  founded.  The  name  Gasteropoda  means 
"stomach-foot,"  the  latter  organ  being  merely  a  thickening  of 


336  MARINE  INVEETEBRATES 

the  ventral  surface  of  the  animal,  giving  to  the  creature,  when 
active,  the  appearance  of  crawling  upon  its  stomach. 

If  a  living  gasteropod  is  placed  in  a  jar  of  sea-water  and  left 
undisturbed  it  will  soon  crawl  up  the  side  of  the  glass  and  thus 
afford  an  excellent  view  of  the  extended  under  surface  of  its  foot. 
The  majority  of  the  gasteropods  are  lethargic  and  slow  in  move- 
ment, but  others  will  be  found  to  be  exceedingly  lively  and  able 
to  creep  up  the  sides  of  the  jar  and  make  their  escape  in  a  sur- 
prisingly short  time.  Further  modifications  of  the  foot  will  be 
mentioned  later. 

THE    MANTLE    CAVITY 

Now  let  us  place  the  animal  with  the  foot  below  and  the  head 
facing  us.  The  spiral  visceral  hump  will  point  back  and  away 
from  the  observer.  The  mantle  covering  the  visceral  portion 
is  thin  and  translucent  like  an  ordinary  skin,  but  at  the  base 
of  the  visceral  mass  the  mantle  suddenly  thickens  very  greatly, 
and  spreads  over  the  dorsal  portion  of  the  foot  or  the  body  like  a 
cloak.  The  space  between  the  body  and  the  loose-lying  mantle 
is  called  the  mantle  cavity,  and  within  this  area  are  to  be  found 
several  important  external  organs.  To  find  these  it  is  well  to  cut 
the  mantle  flap  in  a  straight  line,  beginning  just  back  of  the  head 
and  ending  at  the  point  where  the  mantle  is  attached  to  the  body. 
This  will  most  easily  be  done  with  scissors.  Having  thus  divided 
the  mantle  in  front,  throw  back  the  two  flaps.  On  the  right-hand 
side  (left  of  the  animal),  and  attached  to  the  inner  side  of  the 
mantle  thus  exposed,  will  be  seen  the  branchias,  or  giUs. 

THE  BHANCHI^,    OR   GILLS 

They  consist  of  a  row  of  flattened  filaments  bound  together  at 
the  base  like  the  leaves  of  a  book.  The  blood  is  conveyed  to 
these  gills  by  a  large  vein,  and  is  then  forced  through  the  thinly 
walled  filaments,  being  thus  brought  into  close  contact  with  the 
water,  to  which  it  releases  its  carbon  dioxide,  and  from  which 
it  receives  the  life-giving  oxygen.  In  certain  gasteropods  there 
are  two  sets   of  gills,  one  placed  upon  each  side  of  the  body 


jCtt4/ 


Anatomy  of  the  internal  organs  of  a  female  gasteropod,  viewed  from  the  dorsal  side.  The  roof  of 
the  mantle  cavity  has  been  divided  by  a  longitudinal  incision  and  the  flaps  laid  out,  that  on  the  left 
bearing  the  ctenidium  and  osphradium,  and  that  on  the  right  the  rectum  and  terminal  part  of  the 
oviduct.  The  muscular  dorsal  wall  of  the  body  and  the  introvei*t  have  been  divided  so  as  to  bring 
into  view  the  anterior  part  of  the  alimentary  canal  and  a  portion  of  the  nervous  system.  The 
buccal  cavity  has  been  tilted  up  and  opened  so  as  to  show  the  odontophore,  and  the  esophagus  has 
been  cut  through  near  the  anterior  end.  A  portion  of  the  ventral  wall  of  the  crop  has  been  removed 
so  as  to  bring  the  internal  folds  into  view,  and  the  interior  of  the  nephridium  with  the  contained 
portion  of  the  intestine  has  been  exposed.  The  stomach  is  not  seen,  being  hidden  by  the  neph- 
ridium, and  the  ovary  is  not  represented.  a«.,  anus;  ant.  aort.,  anterior  aorta ;  aur.,  auricle;  Mic, 
buccal  cavity;  cer.buc.con.,  cerebro-buccal  connective;  cer.g.,  cerebral  ganglia;  crop,  crop;  cten., 
ctenidium;  int.,  intestine;  jaio,  jaw;  I.  hue.  g.,  left  buccal  ganglion  ;  I.  sal.  gl.,  left  salivary  gland; 
neph.,  nephridium;  neph.  ap.,  nephridial  aperture;  od.,  odontophore;  oes.,  esophagus;  oes'.,  anterior 
end  of  same,  cut  and  turned  aside;  osph.,  osphradium;  ovid.,  oviduct;  ovid'.,  terminal  thick-walled 
portion  of  oviduct ;  pleur.  g.,  pleural  ganglion  ;  post,  aort,  posterior  aorta ;  post,  oes.,  posterior  esoph- 
agus ;  rod.  s.,  radula  sac  ;  r.  sal.  gl.,  right  salivary  gland;  rect,  rectum;  sal.  du.,  salivary  duct ;  siph., 
siphon;  supra,  g.,   supra-esophageal  visceral  ganglion ;  tent.,  tent&cle;  vent.,  ventricle. 

22  337 


338  MARINE   INVERTEBRATES 

(as  in  the  ideal  mollnsk ) ;  but  the  presence  of  two  sets  of 
gills  only  indicates,  in  these  gasteropods,  that  the  twisting  process 
of  the  viscera,  already  allnded  to  as  so  remarkable  a  feature  of 
this  class,  has  not  proceeded  far  enough  to  destroy  the  functional 
activity  of  one  of  the  gills. 

In  general,  it  may  be  said  that  the  breathing  process  of  mol- 
lusks  does  not  markedly  differ  from  the  respiratory  methods  of 
higher  forms  of  animals.  Whether  the  breathing  is  effected  by 
gills  or  by  a  pulmonary  sac,  the  essential  features  of  the  sj^stem 
are  the  same  as  in  fishes  or  mammals.  There  are,  however,  some 
rather  peculiar  developments  in  the  breathing  system  of  gaster- 
opods  that  are  worthy  of  notice.  The  gills  themselves  differ 
throughout  the  various  orders  of  this  class  both  as  to  their  struc- 
ture and  their  relative  position ;  in  one  of  the  orders  (the  Pul- 
monata)  the  gills  have  entirely  disappeared,  and  are  replaced  by 
a  pulmonary  sac  which  fulfils  the  purpose  of  a  lung. 

It  is  a  generally  accepted  theory  that  all  land  or  air-breathing 
moUusks  were  originally  marine,  but  by  a  gradual  change  in  their 
habits  have  developed  into  terrestrial  forms,  losing  their  gills  and 
acquiring  in  their  place  organs  which  correspond  to  lungs.  The 
theory  is  supported  by  the  fact  that  many  species  of  marine 
moUusks  live  between  tide-marks,  and  for  several  hours  daily  are 
obliged  to  maintain  life  outside  of  their  native  element.  The 
Littorinidce,  which  may  always  be  found  in  abundance  on  both  the 
east  and  the  west  American  coasts,  usually  live  high  above  low- 
tide  line,  and  some  tropical  species  of  this  genus*  actually  live  in 
the  trees  above  the  reach  of  high  tide.  They  have  gills  just  as 
in  Buccimmi  or  Fulgur,  but  the  LiUorina  shell  is  strongl}^  suggestive 
of  certain  land  forms,  and  there  is  reason  to  believe  that  the  genus 
is  in  course  of  evolution  into  a  pulmonate.  On  the  other  hand, 
there  are  to  be  found  in  fresh  water  numerous  genera  which  are 
true  pulmonates,  and  which  are  obliged  to  come  to  the  surface 
every  few  minutes  to  obtain  air.  One  notable  genus  of  marine 
gasteropods  possesses  both  lungs  and  gills,  and  one  marine 
form  has  entirely  lost  its  gills  and  breathes  only  by  means  of 
lungs.  It  is  quite  likely  that  all  mollusks  are  able  to  breathe 
more  or  less  all  along  the  exposed  mantle  surface,  which  is  usually 


GASTEROPODS  339 

crowded  with  capillaries  with  exceedingly  thin  walls.  This  very 
remarkable  method  of  surface  respiration  is  proved  to  exist  in 
the  nudibranch  or  shell-less  marine  Gasteropoda,  for  they  possess 
neither  gills  nor  lungs. 

OSPHRADIUM 

Lying  just  under  the  gills,  and  side  by  side  with  them,  is  a 
smaller,  plume-like  organ  having  the  appearance  of  a  smaller  gill ; 
it  is  called  the  os2)Jiradium.  The  office  of  this  organ  is  not  defi- 
nitely known,  but  the  supposition  is  that  it  is  the  seat  of  the 
olfactory  nerves.  The  osphradia  are  not  always  present,  but  when- 
ever found  they  are  placed  in  close  conjunction  with  the  gills,  in 
order,  probably,  that  the  animal  may  best  determine  the  quality 
of  the  water  brought  by  the  siphon  to  the  breathing-organs.  In 
Biiccinum  the  osphradium  is  especially  prominent.  In  all  mol- 
lusks  the  sense  of  smell  is  highly  developed.  A  dead  animal 
anchored  to  the  bottom  will  very  soon  attract  the  carnivorous 
Mollusca  from  every  direction.  This  is  not  a  bad  way  to  trap 
certain  species  that  live  upon  rocky  stations  and  are  otherwise 
difficult  to  secure  by  the  dredge. 

On  the  left-hand  side  (right  of  the  animal),  and  adhering  to 
the  under  side  of  the  mantle  flap,  which  has  been  thrown  back,  a 
somewhat  inflated  and  convoluted  tube,  the  rectum,  wiU  be  seen. 
It  terminates  in  an  opening  just  within  the  mantle-edge.  By 
the  side  of  this  are  the  renal  and  genital  openings. 

Having  now  examined  the  external  organs,  we  may  investigate 
the  internal  anatomy  of  our  subject.  To  do  this  thoroughly  re- 
quires considerable  skill,  but  for  the  purpose  of  merely  discover- 
ing the  relative  positions  of  the  principal  internal  organs  a  little 
care  only  is  necessary.  The  work  will  be  greatly  facilitated  by 
boiling  the  animal  for  a  few  minutes,  for  this  serves  to  harden 
the  tissues  and  to  separate  the  various  organs  in  a  most  satis- 
factory manner. 

To  begin,  open  the  proboscis  from  the  mouth,  cutting  back  so 
as  to  expose  the  esophagus.  It  will  be  seen  that  the  throat  is 
long  and  very  muscular. 


340 


MARINE  INVERTEBRATES 


RADULA 


Three  rows  of  teeth  from  the  radula  of  Fasciolaria  trapezium. 


Hidden  among  the  red  stripes  of  muscular  fiber  whicli  line 
the  inner  surface  of  the  throat  will  be  found  a  fleshy  strip  cov- 
ered upon  one  side  with  many  transverse  rows  of  chitinous  teeth. 

This  is  the  lingual 
rihhon,  or  radula. 
Remove  as  much 
of  it  as  possible, 
and  examine  it 
with  a  hand-glass. 
The  radula  is  a 
most  important 
organ,  and  is  a  unique  possession  of  Mollusca,  except  the  pelecy- 
pods,  or  bivalves.  Usually*  it  lies  coiled  up  like  a  spiral  when 
not  in  use ;  its  purpose  is  to  tear  and  rasp  food. 

The  radula  has  been  the  subject  of  much  study  by  concholo- 
gists,  and  has  furnished  the  basis  for  an  arrangement  of  the  nu- 
merous sections  of  gasteropods  into  somewhat  well-defined  groups. 
If  the  observer  has  a  strong  glass  he  will  notice  that  each  trans- 
verse row  of  teeth  on  the  ribbon  consists  of  a  median  or  central 
tooth  with  several  points  or  "  cusps."  Ftilgur  has  a  median  tooth 
with  three  cusps ;  Buccinum  one  mth  six.  On  each  side  of  the 
median  tooth  is  a  lateral  tooth,  which  in  Fidgur  wiU  be  seen  to 
have  six  cusps,  and  in  Buccinum  five.  In  many  patterns  of  radulaB 
there  is,  besides  the  me- 
dian and  lateral  teeth,  still 
another  paired  row,  called 
the  marginals.  In  the 
accompanying  figures  are 
given  some  examples  which 
show  small  sections  of  lin- 
gual ribbons.  While  all 
the  radulse  of  moUusks  are  capable  of  being  grouped  by  their 
general  characteristics,  yet  in  no  two  species  of  mollusks  are  the 
radulae  quite  identical. 


Portion  of  the  radula  of  Imbriearia  marmorata. 


GASTEROPODS  341 


VITAL  ORGANS,  STOMACH,  LIVER,  RENAL  GLANDS,  ETC. 

The  digestive  tract  will  be  found  to  widen  out  a  short  distance 
back  into  a  crop  or  stomach,  and,  continuing  still  further,  to  lose 
itself  in  a  soft,  brownish  mass  within  the  coiled  spire,  which  is  the 
liver.  The  very  large  size  of  the  liver  leads  one  to  suspect  that 
Fulgur  and  Buccimtm  must  be  voracious  creatures  to  need  so  large 
an  organ  for  the  secretion  of  bile.  In  many  species  of  mollusks 
the  stomach  and  intestines  are  filled  quite  solidly,  at  times,  with  a 
gelatinous  transparent  substance  called  the  crystalline  stylet.  Just 
why  the  digestive  tract  should  be  clogged  with  this  substance  no 
one  has  yet  been  able  to  explain,  so  here  again  is  a  chance  for 
original  investigation.  The  intestine  curves  about  after  reaching 
the  liver,  and  comes  forward  again  to  appear  once  more  as  the 
rectum,  clinging  to  the  inner  surface  of  the  free  portion  of  the 
mantle. 

Closely  associated  with  the  liver,  but  differing  slightly  in  color, 
is  the  gonad,  or  organ  in  which  the  genital  products  are  formed. 
Situated  dorsally  and  forward  of  the  liver  and  gonad  is  a  large 
renal  gland,  which  may  readily  be  detected  by  its  peculiar  struc- 
ture. In  some  forms  the  kidney  is  closely  associated  with  the 
gonad,  and  seems  to  cooperate  with  the  latter  in  the  generative 
functions. 

HEART  AND  VASCULAR  SYSTEM 

To  find  the  heart,  make  an  incision  into  the  body  just  at  the 
posterior  end  of  the  gills.  The  heart  is  white  and  round,  and  is 
inclosed  within  a  cavity  known  as  the  pericardium  ;  it  has  a  ven- 
tricle and  one  or  two  auricles,  although  in  Biiccinum  and  Fulgur 
there  is  but  one  auricle. 

There  is  nothing  remarkable  about  the  vascular  system  to  dis- 
tinguish it  from  that  of  many  higher  forms  of  animals.  It  is, 
however,  not  completely  closed— by  which  is  meant  that  the  blood 
is  not  always  contained  within  arteries  or  veins,  and  that  it  does 
sometimes  flow  into  other  organs  and  floods  certain  other  body- 
cavities,  although  the  vascular  system  of  mollusks  is  by  no 
means  so  completely  open  as  is  that  of  insects  and  crustaceans. 


342 


MARINE  INVERTEBRATES 


SP' 


Having  examined  the  animal  which  inhabits  the  shell  and 
gained  an  idea  of  its  anatomy,  we  may  now  turn  to  an  inspection 
of  the  honse  which  it  has  built  for  itself,  and  here  we  shall  find  a 
delightful  subject  for  study. 

THE   GASTEROPOD   SHELL 

An  industrious  hour  of  collecting  upon  almost  any  beach  will 
provide  the  student  with  an  abundance  of  interesting  shells. 

Putting  aside  the  bivalves,  the  uni- 
valve or  gasteropod  shells  remain- 
ing should  be  closely  examined  for 
the  purpose  of  becoming  acquainted 
with  their  various  conchological 
features.  The  collector  will  see 
at  once  that  he  has  a  number  of 
species  that  differ  more  or  less 
widely  in  their  general  form,  size, 
texture,  and  sculpture.  Some 
shells  will  be  long  in  proportion  to 
their  width,  with  many  turns  of  the 
spire  which  probably  terminates 
in  a  sharply  pointed  apex;  others 
will  be  almost  round,  with  com- 
paratively few  spiral  turns  which 
end  in  a  blunt  apex,  giving  to  the 
specimen  outlines  suggestive  of  a 
dome.  A  wide  range  of  characters  will  be  found  in  the  mouths 
or  apertures  of  the  shells,  some  being  almost  if  not  quite  round, 
others  oblong  and  with  a  notch  cut  into  the  lower  portion  of  the 
opening,  and  others  possibly  with  this  notch  extended  into  a  sort 
of  semi-inclosed  channel.  A  first  lesson  in  classification  of  the 
MoUusca  may  be  taken  by  dividing  the  results  of  the  first  day's 
collecting  of  univalve  shells  into  groups  according  to  these  promi- 
nent shell-characters. 

A  good  knowledge  of  the  parts  of  a  gasteropod  shell  is  essential 
to  the  student,  and  it  can  readily  be  acquired.  Four  specimens  are 
given  in  the  accompanying  figures,  representing  highly  divergent 


Parts  of  a  gasteropod  shell :  a,  anterior 
canal ;  b,  body-whorl ;  c,  columella ;  I,  outer 
lip;  m,  mouth  or  apertui'e ;  p,  posterior 
canal;  s,  sutures;  sp,  spire;  u,  umbilicus. 


GASTEROPODS 


343 


Murex  tenuispina. 


Acmcea  testudinalis,  from  below 


types  of  marine  gasteropods,  and  their  respective  cliaracteristics 
may  be  noted  by  comparing  them  one  with  another:  Fasciolaria 
tuUpa  (Plate  LXXVI),  a  Floridian  shell-  Folynices  heros,  a  com- 
mon species  found  on  all  the  sandy  shores  of  the  American  At- 
lantic coast ;  Mtirex  tenuispina,  an  Indo-Pacific  species  much  prized 
by  collectors ;  and  Acmcea  testudinalis,  commonly  found  in  Maine 
and  Massachusetts  at  low  tide  clinging  to  rocks.    . 

The  extreme  top  of  the  shell  is  called  the  apex,  and  it  may  be 
either  sharply  pointed  or  obtuse.  Each  turn  is  called  a  ivhorl ; 
the  last  one,  and  always  the  largest,  is  called  the  hody-ivJiorl,  the 
others  collectively  forming  the  sp>ire  of  the  shell.  When  the  ani- 
mal jSrst  emerges  from  the  egg  it  is  always  provided  with  one  or 
two  whorls,  which  generally  may  be  distinguished  at  the  apex  as 
smoother  than  the  rest  of  the  spire,  and  a  faint  line  may  be 
discovered  where  the  shell  began  its  growth  after  birth.     These 


344  MARINE   INVERTEBRATES 

first  whorls  of  embryonic  growth  are  usually  referred  to  as  the 
nepionic  whorls.  The  interstices  between  the  successive  whorls 
are  called  sutures,  and  these  lines  of  juncture  may  be  shallow  or 
deep  according  to  the  convexity  of  the  whorls.  The  sculpturing 
of  the  whorls  is  often  of  great  complexity,  and  exhibits  nodules, 
varices,  ribs,  revolving  strim,  spinous  processes,  and  lines  of  growth.  It 
frequently  happens  that  there  is  a  complete  absence  of  any  sculp- 
turing whatever,  the  whole  surface  of  the  shell  being  perfectly 
smooth,  save  for  the  faint  lines  of  growth  to  be  detected  only 
under  a  magnifying-glass.  The  outer  edge  of  the  mouth  or 
aperture  of  the  shell  is  called  the  oiiter  Up.  This  may  be  more  or 
less  thickened,  expanded,  or  simple.  The  inner  lip  is  called  the 
columella,  and  may  be  greatly  extended  anteriorly.  When  the 
mouth  of  the  shell  is  round,  and  there  is  no  notch  or  indentation 
either  above  or  below,  it  is  said  to  be  continuous. 

The  anterior  canal  is  for  the  accommodation  of  the  siphon  of 
the  animal,  which,  as  noted  above,  may  be  very  long  or  almost 
entirely  absent;  therefore  the  character  of  the  shell  generally 
indicates  whether  or  not  the  animal  itself  possesses  a  long  siphon. 
There  is  in  some  forms  a  notch  at  the  upper  extremity  of  the 
mouth,  which  is  for  the  accommodation  of  the  anal  discharges. 
When  present  it  is  called  the  posterior  canal. 

It  will  be  noted  that  all  the  specimens  figured  as  examples, 
save  one,  are  spiral,  the  coils  revolving  about  an  imaginary  axis. 
When  the  whorls  are  not  too  closely  coiled  there  is  left  open  to 
the  view  a  hollow  space  throughout  the  entire  length  of  the  shell, 
which  is  called  the  umbilicus.  When  the  coils  of  the  shell  are 
very  compact  there  is  no  umbilicus  to  be  seen.  The  umbilical 
opening  may  be  very  large,  giving  a  clear  view  of  the  inner  sur- 
faces of  all  the  whorls  right  through  to  the  apex.  The  usual 
gasteropod  shell  is  in  reality  a  hollow  tube  wound  about  an 
imaginary  axis.  Since  the  tube  increases  in  size  as  it  progresses, 
the  base  of  the  shell  is  necessarily  wider  and  larger  than  the  apex. 
Thus  all  gasteropod  shells  may  be  reduced  in  shape  to  the  single 
type  of  a  cone  or  top,  modified  by  the  excessive  length  or  short- 
ness of  the  spire,  or  otherwise  altered  by  special  peculiarities.  In 
Folynices  duplicata  (page  368),  it  will  be  observed  that  while  the 


GASTEROPODS  345 

umbilicus  is  fairly  large,  its  external  opening,  in  the  adult  shell, 
has  been  almost  completely  closed  by  a  callous  process  thrown  off 
from  the  inner  or  columellar  lip. 

Gasteropod  shells  may  be  sinistral  or  dextral,  according  as  the 
whorls  turn  to  the  left  or  right.  The  great  majority  of  marine 
species  are  dextral,  having  the  opening  on  the  right,  although  a 
few  species  exhibit  the  curious  property  of  being  constructed  upon 
either  the  one  or  the  other  plan  without  apparent  reason.  Sinistral 
specimens  of  many  normally  dextral  species  have  been  discovered, 
but  they  are  so  rare  as  to  warrant  the  belief  that  such  specimens 
are  merely  deformities  or  monstrosities  resulting  from  some  acci- 
dent of  birth. 

The  collector  will  soon  learn  to  distinguish  between  young  and 
adult  specimens,  for  those  finishing  touches  of  wonder  and  beauty 
which  the  moUusk  gives  to  his  protective  covering  are  made  only 
by  the  adult.  The  outer  lip  of  young  gasteropod  shells  is  usually 
thin  and  fragile ;  even  if  slightly  thickened,  it  has  an  unformed 
or  unfinished  appearance. 

Shells  differ  greatly  in  their  structure,  many  species  being  por- 
celanous  like  chiua,  others  glassy,  and  many  more  are  of  a 
softer  chalky  composition.  In  the  latter  case  the  shell  is  usually 
covered  with  a  thick  membranous  skin,  which,  when  removed, 
leaves  a  dull,  lusterless,  white  body  beneath.  Shells  of  this  tex- 
ture, when  cast  upon  the  beach,  soon  yield  to  the  weathering 
action  of  sun  and  air.  The  porcelanous  shells  are  composed  of 
successive  layers  of  carbonate  of  lime,  throughout  which  is  a 
filmy  membranous  framework  of  a  substance  similar  to  that  of 
which  the  covering  of  the  Crustacea  is  formed.  The  mode  of 
deposition  of  the  various  layers  of  crystalline  calcic  carbonate 
and  the  peculiar  lineation  of  their  outer  surfaces  give  rise  to  the 
iridescent  or  nacreous  appearance  of  some  shells. 

With  the  exception  of  those  species  in  which  the  mantle  of  the 
animal  is  extended  over  the  edge  of  the  aperture  and  more  or 
less  envelops  the  entire  test,  there  is  an  outer  skin  of  membra- 
nous or  organic  matter  which  overlies  the  surface  of  the  shell. 
This  skin  is  sometimes  quite  thick,  often  hairy,  and  is  usually  of 
a  dull  greenish-  or  brownish-yellow  color.     In  many  genera  this 


346  MARINE  INVERTEBRATES 

outer  covering  of  the  shell  is  excessively  thin.  In  old  speci- 
mens the  epidermis  is  usually  worn  away  from  the  apical  whorls. 
It  often  happens  that  the  shells  of  the  most  exquisite  colors  and 
markings  are  thus  rendered  somber  and  unattractive  by  their 
tenants  during  life ;  when  the  animal  dies,  or  when  such  speci- 
mens are  kept  in  a  cabinet  for  a  period  of  time,  the  epidermis 
dries,  cracks,  and  falls  off,  revealing  the  wealth  of  color  and 
design  beneath. 

The  growth  of  the  gasteropod  shell  is  accomplished  by  the 
exudation  from  the  margin  of  the  animal's  mantle  of  a  liquid 
containing  the  shelly  matter  in  solution.  The  mantle-edge  is 
provided  with  a  complicated  system  of  glands  and  pores,  from 
which  is  secreted  this  "  stony  liquor."  This  more  or  less  viscous 
liquid,  containing  the  carbonate  of  lime  and  the  other  inorganic 
materials  of  which  the  shell  is  composed,  hardens  upon  exposure, 
and  the  shelly  matter  is  then  deposited  in  crystalline  form  around 
the  edges  or  lip  of  the  shell  aperture.  The  gasteropod  shell 
therefore  grows  by  the  continual  building  out  of  its  aperture 
through  successive  depositions  of  shelly  matter  at  the  extreme 
edge  of  the  lip.  At  the  extreme  edge  of  the  mantle  margin  are 
situated  those  glands  which  secrete  the  materials  for  the  epider- 
mis of  the  shell,  and  as  one  would  therefore  expect,  this  outer- 
most layer  of  epidermis  is  first  produced  in  the  advancing  growth 
of  the  shell.  There  also  are  situated  the  pigment-glands,  which 
produce  the  color-secretions.  The  various  layers  of  the  shelly 
substance  are  successively  deposited  inside  the  mouth  of  the  shell 
by  glands  situated  just  back  of  the  extreme  edge  of  the  mantle 
margin.  Thus  in  the  growth  stage,  if  one  could  examine  closely 
the  aperture  of  a  gasteropod  shell,  one  would  observe  at  the  ex- 
treme tip  of  the  lip  this  projecting  epidermis,  just  beneath  it  and 
just  inside  the  aperture  a  thin  deposit  of  shelly  matter,  just  be- 
neath this,  and  farther  in,  another  layer,  and  still  farther  in  a 
third  layer. 

The  growth  of  nearly  all  gasteropod  shells  is  marked  by  periods 
of  rest.  During  the  inactive  seasons  the  creature  may  thicken 
the  edge  of  the  aperture  to  a  greater  or  less  extent  by  an  extra 
deposit  of  shelly  matter,  for  otherwise  the  thin  lip  might  soon  be 


GASTEROPODS  347 

injured  or  broken.  These  places  where  the  lip  was  thickened, 
as  a  temporary  protection  until  the  young  animal  decided  to 
continue  building,  appear  on  the  surface  of  adult  shells,  and 
persist  as  varices,  "raised  lines  of  growth,"  "longitudinal  ribs," 
etc.  Such  forms  of  sculptural  markings  generally  occur  at  equi- 
distant points  and  preserve  a  scheme  of  regularity  which  would 
indicate  that  the  periods  of  rest  were  of  seasonal  occurrence.  All 
irregularities  and  all  surface  features  of  the  external  shell  simply 
reflect  certain  peculiarities  of  the  mantle  margin  of  the  animal ; 
all  spinous  processes,  for  instance,  as  in  the  marvelous  Murex 
tenuispina,  indicate  the  existence  of  finger-like  processes  extend- 
ing from  the  mantle  margin,  which  once  occupied  the  hollow 
thorns  projecting  from  the  shell.  When  the  outer  surface  of  a 
shell  is  devoid  of  any  sculpturing  and  is  perfectly  smooth,  one 
may  assume  that  the  mantle  margin  of  the  animal  was  simple.  If 
the  edge  of  the  lip  has  a  crenulated  appearance  and  the  surface  of 
the  whorls  is  decorated  with  revolving  ribs,  the  mantle  margin 
was  probably  folded  or  wavy.  There  can  be  no  doubt  but  that  the 
entire  mantle  surface  is  provided  to  some  extent  with  glands  for 
the  secretion  of  shelly  matter,  for  if  any  portion  of  the  shell  is 
accidentally  injured  the  animal  soon  repairs  the  break  with  a  cal- 
careous deposit.  But  such  repairs  are  never  homogeneous  in 
texture  with  the  other  parts  of  the  shell  of  normal  growth ;  the 
patches  are  never  covered  externally  with  an  epidermis,  and  they 
are  always  devoid  of  color.  The  function  of  the  epidermis  is  to 
protect  the  calcareous  shell  from  the  corroding  agents  contained 
in  sea-water.  Hence  it  is  that,  when  the  epidermis  is  removed, 
"  dead  shells  "  exposed  to  the  influence  of  the  water  or  the  weather 
soon  lose  their  brilliancy  and  luster,  and  become  undesirable  for 
specimens  either  for  the  cabinet  or  for  study.  It  often  happens 
that  living  shells,  inhabiting  a  region  where,  for  one  cause  or 
another,  the  water  is  highly  charged  with  impurities  of  an  acid 
nature,  are  discovered  to  be  badly  corroded  about  the  apex,  where 
the  epidermis  is  thin  and  likely  to  be  rubbed  off.  For  this  reason 
specimens  collected  in  harbors  near  large  cities  or  near  the  mouths 
of  rivers  are  apt  to  be  poor  and  defective. 

The  inner  surface  of  all  shells,  if  not  actually  nacreous,  is 


348  MARINE  INVERTEBRATES 

always  perfectly  smooth.  When  foreign  substances,  such  as 
grains  of  sand,  enter  the  shell  and  cannot  be  removed  by  the 
animal,  the  irritation  caused  thereby  to  the  soft,  fleshy  creature 
induces  discharges  of  a  liquid  from  the  glandular  surface  of  the 
mantle,  which  hardens  about  the  offending  substance  and  glazes 
it  over  with  a  smooth,  pearly  deposit. 

Acmcea  testudinalis  (page  343)  presents  a  special  type  of  gastero- 
pod  shell  which  is  found  in  several  families.  Here  the  spire 
seems  to  be  wholly  absent,  and  the  entire  shell  consists  of  but  one 
large  body-whorl.  There  are  very  many  of  these  patelliform 
species,  inhabiting  many  seas  and  belonging  to  many  different 
genera,  and  in  nearly  all  cases  their  embryonic  shells  display  a 
spiral  form.  After  birth  the  animal  does  not  build  his  house 
upon  the  spiral  plan,  but  expands  the  shell  into  one  large  shield- 
like covering.  The  student,  however,  mast  not  presume  that 
Acmcea  is  an  ancestral  type  just  because  the  simple  character  of 
the  shell  is  suggestive  of  the  model  chosen  to  represent  a  schematic 
mollusk  5  anatomically  Acmcea  presents  the  complications  of  body- 
torsion  which  show  a  very  considerable  evolutionary  change, 
and  indicate  that  its  simple  shell  is  probably  a  degenerate  form  of  a 
once  more  highly  developed  and  convoluted  one. 

The  forms,  the  architecture,  and  the  painting  of  gasteropod 
shells  are  so  infinite  in  variety  that  it  would  be  unwise  to  attempt 
a  description  of  their  marvels.  A  close  observer  of  nature's 
works  soon  becomes  prepared  for  every  surprise,  but  he  never 
ceases  to  be  charmed  and  fascinated  b}^  his  new  discoveries.  The 
careful  student  alone  can  learn  really  to  see  and  appreciate  the 
wonders  of  nature,  and  this  is  especially  true  in  the  study  of  the 
MoUusca. 

CLASSIFICATION   OF   GASTEROPODS 

The  Gasteropoda  far  exceed  all  the  other  divisions  of  the  Mol- 
lusca  in  the  number  of  their  genera  and  species.  Apparently 
this  has  not  always  been  the  case.  There  is  evidence  tending  to 
show  that  in  past  geological  epochs  the  pelecypods  (the  bivalve 
shells)  outnumbered  the  gasteropods,  but  that  in  the  course  of 
time  the  increase  in  the  genera  of  gasteropods  has  been  more 


"*        GASTEROPODS  349 

rapid.  To  judge  also  from  the  very  large  number  of  extinct  fam- 
ilies among  the  cephalopods,  which  once  flourished  in  astonishing 
abundance,  it  would  appear  that  they  are  a  dying  race. 

The  classification  of  the  Gasteropoda  is  primarily  a  division 
into  three  great  orders :  the  Opisthohranchiata,  the  Prosobran- 
cMata,  and  the  Pulmonata.  The  Fulmonata,  which  include  the 
land  and  fresh-water  gasteropod  shells,  are  characterized  by  the 
presence  of  a  breathing-sac,  or  lung,  instead  of  gills.  They  are, 
therefore,  essentially  air-breathers,  and  would  perish  if  kept  too 
long  under  water.  The  Opisthohranchiata  and  Frosohranchiata 
are  marine,  and,  like  all  animals  which  breathe  by  means  of  gills, 
soon  die  when  removed  from  the  water.  We  have  already  noted, 
however,  how  some  genera  of  marine  gasteropods  that  find  their 
station  about  high-tide  mark  are  able  to  live  for  considerable 
periods  out  of  the  water,  notwithstanding  the  fact  that  they  are 
fully  equipped  with  gills  and  not  possessed  of  lungs.  Indeed, 
there  is  one  large  family  of  prosobranchs  (the  Cydostomatidce) 
that  has  become  entirely  terrestrial  in  habit,  its  members  having 
lost  their  gills  and  acquired  lungs,  but  their  organization  other- 
wise is  so  essentially  that  of  the  prosobranchs  that  they  have 
never  been  considered  as  pulmonates. 

The  main  difference  between  these  two  orders  of  marine  gas- 
teropods is  that  in  the  prosobranchs  the  breathing-organs  (the 
gills)  are  placed  in  a  position  forward  of  the  heart,  and  the  de- 
gree of  torsion  (page  330)  characteristic  of  this  molluscan  class  has 
been  continued  until  the  auricle  of  the  heart  is  in  front  of  the 
ventricle.  There  is  always  a  shell,  usually  spiral,  and,  with  few 
exceptions,  an  operculum.  In  the  opisthobranchs,  on  the  other 
hand,  the  relative  position  of  the  heart  and  gills  is  reversed,  and 
they  further  differ  from  the  prosobranchs  in  that  the  sexes  are 
always  united  in  each  individual.  The  opisthobranchs  are  not  al- 
ways provided  with  a  shell.  One  division  of  the  order,  known  as 
the  "  nudibranchs,"  are  entirely  nakedo  These  are  commonly  called 
the  '^  sea-slugs,"  and  are  to  be  found  crawling  about  the  marine 
vegetation  in  shallow  water,  in  tide-pools,  and  on  the  piling  of  old 
docks.  Curiously  enough,  the  sea-slugs  (see  page  354)  have  no  gills 
at  all,  but,  having  lost  these  apparently  essential  organs,  are  ena- 


350  MARINE   INVERTEBRATES 

bled  to  '^  breathe  water '-  through  their  skin.  They  are  wonder- 
fully beautiful  creatures,  and  the  collector  must  not  fail  to  secure 
some  specimens,  put  them  into  a  jar  of  sea- water,  and  watch 
them  expand. 

There  are  other  more  superficial  differences  between  the  proso- 
branchs  and  the  opisthobranchs,  which  will  enable  even  a  beginner 
to  distinguish  them  at  a  glance.  When  the  latter  are  possessed 
of  an  external  shell,  it  is  bulbous,  generally  glassy,  and  with  a 
simple  lip,  the  aperture  extending  the  entire  length  of  the  shell. 
Again,  the  mantle  or  the  propodium  of  the  foot  is  greatly  ex- 
tended and  usually  covers  the  shell  almost  wholly. 

With  the  exception  of  the  nudibranchs,  which  are  common  aU 
along  the  Atlantic  shore,  especially  north  of  Cape  Cod,  there  are 
very  few  opisthobranchs  to  be  found  in  American  waters.  Their 
shells  are  not  very  abundantly  found  anywhere,  though  in  Florida 
there  are  two  or  three  species  which  an  untrained  collector  might 
discover. 

Practically  all  the  gasteropod  or  univalve  shells  that  will  be 
taken  by  the  ordinarily  expert  collector  along  the  shore  are  proso- 
branchs.  This  order  includes  the  great  majority  of  marine  gastero- 
pods,  and  is  entitled  to  the  distinction  of  claiming,  in  the  great 
number  of  its  genera  and  species,  the  most  startling  eccentricities 
of  form  and  color  to  be  found  among  the  Molhisca,  if  not  among 
all  marine  invertebrates. 

Only  those  species  which  are  actually  abundant  on  the  Atlantic 
and  Pacific  shores  of  the  United  States,  and  which  are  likely  to  be 
found  by  the  untrained  collector,  are  selected  from  the  long  list 
of  forms  which  belong  to  the  three  faunal  regions  involved. 

ORDER  OPISTHOBRANCHIATA 

Suborder  tectibranchiata 

To  avoid  confusion,  it  is  well  to  keep  the  systematic  table  in 
view: 

Class  Orders  Suborders 

(  OPISTHOBRANCHIATA  S  TECTIBRANCHIATA 

GASTEROPODA       ]  prosobranchiata  I  nudibranchiata 

(  PULMONATA 


PLATE   LXV. 


Btdla  occidentalis,  enlarged. 
Lottia  gigantea,  inside  view. 


Bulla  nebulosa. 
Fissurella  alternata. 


GASTEROPODS  351 

As  has  already  been  remarked,  shell-bearing  opisthobranchs 
are  not  abundantly  represented  in  number  of  species  in  North 
American  waters.  South  of  Cape  Cod,  in  muddy  bays  and  well- 
sheltered  places,  the  little  shell,  Haminea  solitaria,  may,  however, 
often  be  found  in  considerable  numbers. 

Genus  ITaminea 

He  solitaria.  Like  all  external  opisthobranch  tests,  the  shell  of  this 
species  is  thin  and  fragile,  and  would  appear  to  be  of  small  importance 
to  the  creature  it  only  partially  protects.  It  is  devoid  of  spire,  is 
shining  bluish- white,  sometimes  brownish  in  color,  and  is 
marked  with  revolving  grooves,  which,  being  cut  across  by 
irregular  growth-lines,  give  its  surface  a  faintly  decussated 
appearance.  The  aperture  is  as  long  as  the  shell ;  the  colu- 
mella is  incurved.  This  little  species  is  especially  abundant 
in  shallow  water  about  Vineyard  Sound  and  in  Peconic  Bay. 

Genus  Bulla 

B.  occidentalis.  This  species,  which  is  found  in  the  waters  of 
Florida  on  all  sandy  beaches,  is  a  relative  of  the  Northern  species  just 
described.  The  shell  is  larger  than  that  of  Haminea  solitaria,  and  has 
a  color-pattern  of  mottled  or  clouded  reddish-brown  on  a  white  foun- 
dation. There  is  no  spire ;  there  is  a  pit  in  place  of  an  apex ;  and  the 
aperture  extends  the  full  length  of  the  shell.  To  the  naked  eye  the  surface 
appears  smooth  and  shining.  It  is  an  exceedingly  variable  species, 
occurring  aU  through  the  West  Indies,  but  not  north  of  Florida.  The 
shores  of  the  keys  along  the  west  coast  of  Florida  are  often  strewn  with 
these  shells  after  storms.  The  animal,  like  all  the  sheU-bearing  opistho- 
branchs,  is  very  large  as  compared  with  the  shell,  and  the  large  mantle 
folds  recurve  upward,  almost  completely  hiding  the  shell  from  view. 
(Plate  LXV.) 

B,  nebulosa.  This  is  one  of  the  largest  and  finest  species  of  the 
family  Bullidce.  It  is  found  on  the  coast  of  California  south  of  San 
Francisco.  The  shell  is  much  larger  than  that  of  either  of  the  Atlantic 
species  mentioned  above,  but  very  closely  resembles  them  in  outline, 
although  it  is  built  upon  a  more  generous  plan  and  is  more  richly 
painted.  It  is  brownish,  mottled  with  white  and  yellow  patches,  and  is 
very  suggestive  of  certain  kinds  of  birds'  eggs.  The  animals  have  a 
greatly  extended  mantle  which  almost  completely  envelops  the  shell. 
The  foot  is  extremely  large,  with  great  wing-like  developments  upon 
each  side,  called  parapodia.  Some  species  of  Bulla  have  been  seen  to 
swim  by  means  of  the  lazy  flapping  of  the  parapodia.     (Plate  LXV.) 

SEA-HARES 

Closely  allied  to  these  outer-shell-bearing  opisthobranchs  is  a 
large   and  important   group   of   tectibranchs,   known  as  ''sea- 


352  MARINE  INVERTEBRATES 

hares."  They  have  a  mantle  so  greatly  developed  that  it 
actually  covers  the .  shell,  and  its  edges  unite  and  fuse  over  the 
top.  The  shell,  in  consequence,  having  almost  ceased  to  be  of 
use  as  a  protection,  has  degenerated  into  a  mere  horny  plate, 
and  has  lost  all  resemblance  to  the  ordinary  gasteropod  sheU. 
Having  practically  lost  its  protective  office  and  become  a  mere 
internal  plate,  it  is  quite  probable  that  it  will  in  time  wholly 
disappear.  The  gills  of  the  sea-hares  are  concealed  under  a  flap 
of  the  mantle,  their  position  being  posterior  to  the  heart.  The 
most  conspicuous  representative  of  this  type  of  tectibranchs  in 
the  United  States  is  the  following : 


Genus  Aplysia 

A,  Wilcoxii,  This  species  appears  at  times  in  vast  numbers  in  the 
waters  of  Florida,  imtU  the  sea  may  truly  be  said  to  be  fairly  ahve  with 
them.  They  swim  lazily  with  a  waving  motion  of  the  parapodia.  They 
disappear  as  mysteriously  as  they  come,  and  for  months  not  a  specimen 
will  be  seen.  There  is  a  variety  of  this  Floridian  Aplysia  which  occurs 
at  Cape  May,  but  no  sea-hares  are  to  be  found  north  of  that  point.  The 
tropical  Pacific  furnishes  an  astonishing  wealth  of  these  creatures, 
belonging  to  many  genera  and  species,  and  among  them  are  some  of  the 
most  beautiful  of  the  invertebrate  animals. 


Suborder  nudibranchiata 

The  opisthobranchs  are  divided  into  two  suborders,  the  second 
of  which  is  called  Nudibranehiata.  The  name  is  well  chosen  and 
very  suggestive,  for  it  means  ^'  naked  or  exposed  gills  "  -,  but  this 
anatomical  feature  is  only  one  of  the  peculiarities  of  this  suborder. 
The  nudibranchs  are  commonly  known  as  '^  sea-slugs  " ;  for,  like 
the  land-slugs,  which  are  also  true  mollusks,  they  possess  no 
shell  at  all.  That  they  at  one  time  carried  a  shell  is  evident  from 
the  fact  that  they  are  born  with  a  rudimentary  testaceous  cover- 
ing, which  soon  afterward  disappears. 

A  striking  peculiarity  of  the  nudibranchs  is  that  the  conven- 
tional molluscan  mantle  is  not  usually  apparent.  Instead  of 
seeing  the  usual  flaps  or  folds  of  the  mantle  which  more  or  less 
encircle  mollusks,  and  which  one  seems  to  have  a  right  to  expect, 


GASTEROPODS  353 

they  are  entirely  absent,  and  tlie  body  of  the  sea-slug  assumes  in 
consequence  a  worm-like  appearance.  Other  notable  features  of 
the  nudibranclis  are  the  great  number  of  tentacular  processes  that 
usually  project  from  the  dorsal  region  of  the  animal,  and,  in  many 
of  the  genera,  an  entire  absence  of  gills.  When  the  gills  are 
present,  as  is  the  case  in  several  of  the  nudibranch  families,  they 
are  not  placed  along  the  side  of  the  animal,  where  one  would 
naturally  look  for  them,  but  are  arranged  in  the  form  of  a 
rosette  of  plume-like  processes  situated  in  the  posterior  dorsal 
region,  or,  in  other  words,  on  the  animal's  back. 

Nudibranch s  are  commonly  to  be  found  all  along  the  Atlantic 
and  Pacific  coasts  of  North  America,  and  more  especially  in  the 
colder  waters  north  of  Cape  Cod.  They  are  essentially  littoral, 
and  live  upon  algae  in  shallow  water,  upon  eel-grass  in  sheltered 
places,  and  in  tide-pools,  where  there  is  more  or  less  vegetation. 
They  crawl  about  the  fronds  of  algae,  or  swim,  foot  upward,  with 
a  gentle  and  undulating  motion,  or,  when  caught  between  tides, 
may  be  seen  clinging  to  the  under  surface  of  rocks.  Protective 
resemblances  have  been  so  remarkably  developed  in  the  nudi- 
branchs  that  they  are  not  always  easy  to  discover  5  indeed,  one 
may  actually  be  looking  at  one  for  some  time  without  suspecting  it 
to  be  other  than  some  torn  fragment  of  seaweed. 

There  are  many  species  belonging  to  several  genera  which  fre- 
quent the  Maine  and  Massachusetts  coasts,  but  those  most  likely 
to  be  encountered  are  the  following : 


Genus  Dendronotus 

D.  arborescens.  This  species  is  about  one  inch  long  and  variable 
in  color,  but  is  usually  reddish-brown  or  rose.  There  are  no  tentacles, 
but  in  their  place  are  two  antler-like  appendages  pointing  forward  and 
branched  like  a  tree.  All  along  the  back  are  two  rows  of  these  curiously 
branched  processes,  which  give  to  the  animal  the  appearance  of  a  plant. 
These  cerata,  or  dorsal  papillae,  are  delicately  transparent,  contractile, 
and  richly  colored.  The  function  of  these  papillse  is  not  fully  known. 
As  the  animal  has  no  specialized  breathing-organs,  it  is  reasonable  to 
suppose  that  respiration  is  carried  on  through  the  outer  skin  and  per- 
haps all  over  the  surface  of  these  branched  papillse.     The  liver,  which 

23 


354 


MARINE  INVERTEBRATES 


in  most  nudibrauchs  is  extremely  large  and  completely  surrounds  the 
stomach,  in  Dendronotus  also  extends  into  these  dorsal  cerata,  so  that 
they  may  have  some  sort  of  digestive  function. 


Dendronotus  arhorescens. 


Genus  Molls 

^,  papulosa.  This  is  probably  the  commonest  nudibranch  upon 
the  North  Atlantic  coast,  and  it  occurs  as  frequently  in  European 
waters.  It  may  readily  be  found  clinging  to  stones,  alg£e,  the  piling  of 
wharves,  eel-grass,  etc.,  in  bays  or  in  rocky  tide-pools.  The  color  is 
yellowish-gray  to  orange,  with  purplish  or  olive 
spots.  The  cerata  are  very  numerous,  and  cover  the 
dorsal  portion  of  the  animal  save  for  an  open  space 
along  the  middle  of  the  back.  There  are  two  sets  of 
tentacles,  the  two  dorsal  and  the  two  simple  labial 
tentacles.  The  foot  tapers  behind  to  a  sharp  point, 
and  is  truncate  in  front.  As  in  Dendronotus,  the 
liver  is  diffused  into  the  cerata,  which  in  ^olis  are 
simple  tubular  processes  without  the  branching 
character  of  those  of  the  former.  Both  species  lay 
their  eggs  in  a  gelatinous,  bobbin-like  cord,  which 
is  hung  in  festoons  over  rocks  or  upon  zoophytes,  or 
at  times  they  wind  the  cord  in  a  coil  upon  the  sur- 
faces of  stones.  When  the  young  first  hatch  out, 
they  are  provided  with  a  glassy  nautiloid  shell,  a  fact 
which  would  indicate  that  at  some  remote  period  they 
were,  like  most  moUusks,  provided  with  a  shell,  ^olis  swims  in  an  in- 
verted position,  and  is  at  times  exceedingly  active.  It  is  very  variable  in 
coloring  and  in  the  number  of  cerata. 


^olis  papulosa. 


Genus  Doris 

JD,  hilamellata.  In  Boris  we  find  a  quite  different  type  of  nudi- 
branch from  that  presented  by  the  two  genera  Dendronotus  and  ^olis. 
In  one  there  were  numerous  branched  cerata  or  dorsal  papillae,  in  the 
other  many  plain  cerata,  and  in  neither  case  were  there  any  specialized 


GASTEROPODS  355 

breathing-organs,  In  Doris,  however,  there  are  no  dorsal  papillse  at  all, 
the  back  being  covered  with  calcareous  spicules,  which  form  a  sort  of 
secondary  shell.  There  is  a  cir- 
clet, or  rosette,  of  retractile 
plume-like  gills,  or  branchiae, 
placed  in  the  middle  of  the  back 
posteriorly.  There  are  various 
species  of  Boris,  and  of  closely 
allied  genera  belonging  to  the 
family  Borididce,  which  are  to  be 
found  along  the  New  England  Boris  huameuata. 

coast  in  tide-pools  and  among 

rocks.  Those  seen  by  the  writer  never  appeared  to  be  other  than  very 
sluggish  creatures,  and  proved  to  be  rather  unsatisfactory  tenants  of  the 
aquarium. 

When  discovered  at  low  tide  upon  moist  seaweed  or  stones,  or 
when  disturbed  in  the  water,  nudibranchs  often  appear  like  small 
lumps  of  jelly-like  tissue,  without  a  single  attractive  feature.  It 
is  only  when  they  are  placed  in  a  jar  of  sea-water  and  left  un- 
molested for  a  few  moments  that  they  unfold  their  beauties  to  the 
view.  On  the  Pacific  coast  there  are  numerous  species  of  nudi- 
branchs, occupying  corresponding  shore  stations  and  exhibiting 
the  same  degree  of  high  coloration.  There  are  over  a  thousand 
species  of  sea-slugs  scattered  about  the  various  seas.  They  find 
their  greatest  development  in  tropical  waters,  and  for  brilliancy 
of  tint  and  variation  in  form  are  unequaled  by  any  other  class  of 
animal  life,  save  perhaps  the  butterflies. 


ORDER  PROSOBRANCHIATA 

To  this  exceedingly  large  and  comprehensive  order  of  gastero- 
pods  belong  the  great  majority  of  univalve  mollusks.  In  point 
of  number  of  genera  and  species  and  in  abundance  of  individuals, 
the  prosobranchs  probably  exceed  all  the  other  orders  of  mollusks 
combined.  They  may  be  called  the  typical  gasteropods,  the 
shell  being  univalvular  and  generally  spiral,  and  the  animal  ex- 
hibiting the  singular  torsion  of  the  visceral  mass  which  has  placed 
the  breathing-organs  forward  of  the  heart.  They  are  provided 
with  an  operculum  (placed  upon  the  posterior  dorsal  portion  of 
the  foot),  which  is  used  to  close  the  aperture  of  the  shell  against 


356  MARINE  INVERTEBRATES 

enemies  when  the  animal  retires  within  its  fortress.  They  are 
all  marine  except  a  very  few  families,  which,  supposedly  of  marine 
derivation,  have  become  terrestrial  in  habit. 

The  prosobranchs  are  further  subdivided  into  suborders  accord- 
ing to  certain  peculiarities  of  the  heart  and  breathing-organs. 
There  is  a  group  of  these  prosobranchs  which  gives  evidence  of 
an  inferior  degree  of  that  visceral  torsion  which  is  always  found 
in  the  gasteropods.  In  this  group,  or  suborder,  the  heart  has  two 
auricles,  and  there  is  a  pair  of  gills  instead  of  only  a  single  one. 
Other  internal  organs  are  paired  just  as  they  were  represented  to 
be  in  the  schematic  mollusk.  This  group  also  seems  to  show  its 
primitive  character  in  the  want  of  a  proboscis  and  a  siphon^  or, 
in  some  families,  by  having  the  ventricle  of  the  heart  traversed 
by  the  intestinal  canal,  just  as  in  the  lower  class  of  mollusks, 
which  includes  the  clams  and  oysters.  For  the  most  part  the 
shells  of  this  group  are  not  typically  spiral,  but  are  patelliform, 
shield-like  coverings,  with  only  a  suggestion  of  a  spiral  form  at 
the  very  tip  of  the  apex.  This  group  of  primitive  prosobranchs 
is  included  in  the  following  suborder : 

Suborder  diatocahdia 

This  suborder  is  named  from  the  presence  of  two  auricles  in 
the  heart. 

Family  acumidm 

The  first  family  to  be  noted  is  the  Acmceidce.  Its  principal 
genus,  Acmcea,  is  well  represented  on  both  the  east  and  the  west 
coast  of  the  United  States. 

Genus  Acmcea 

A,  testudinalis.  This  species  is  found  in  vast  numbers  all  along  the 
New  England  shore,  clinging  to  the  rocks  between  tides.  They  are  usu- 
ally called  limpets.  The  shell  is  solid,  conical,  with  an  oval  outline,  and 
with  no  trace  of  a  spiral  form  in  the  adult.  When  the  shell  is  thor- 
oughly cleaned,  it  generally  presents  a  mottled  coloration  of  pale  green, 
brown,  and  white.    Inside  it  is  white  and  nacreous,  with  a  large  brown 


GASTEROPODS  357 

area  under  the  apex.  The  animal  has  a  powerful  foot,  by  means  of 
which  it  is  enabled  to  cling  to  a  rock  with  great  strength.  In  order  to 
dislodge  it,  it  is  necessary  to  approach  carefully,  and,  taking  the  crea- 
ture unawares,  quickly  shp  a  broad  knife-blade  under  the  foot,  otherwise 
it  is  quite  impossible  to  tear  it  from  its  resting-place.  A.  testudinalis  lives 
entirely  between  tides,  and  ranges  from  the  northernmost 
waters  to  New  York.  It  feeds  upon  algae  and  is  a  very 
sluggish  animal.  It  has  been  said  to  leave  its  resting-place 
and  wander  about  in  search  of  food,  returning  to  its  original 
and  usual  spot  when  the  tide  begins  to  ebb.     (Page  343..) 

A,  testtuUnalis,  variety  alveus.  This  variety  is  smaller, 
more  fragile,  and  oblong.  It  lives  upon  eel-grass,  its  oblong 
shell  being  adapted  to  the  narrow  leaves  of  the  grass.  The 
coloration  is  brighter  —  reddish-brown  spots  on  a  white  sur- 
face.     It  is   exceedingly   common  on  the   New   England    ^ZTusXtT^' 

coast.  alveus. 

A.  mitra.     On  the  Pacific  coast  there  are  a  number  of 
acmaeas.    A.  mitra  is  often  found  dead  upon  the  beaches.     It  is  conical 
in  form  and  pure  creamy- white  in  color.      It  looks  very  much  like  a 
clown's  pointed  cap. 

A,  patina.  This  is  also  very  abundant  in  California.  Outside  it  is 
dark  in  color  and  is  often  in  crusted  with  mineral  deposits.  Within  there 
is  a  dark  ring  around  the  edge,  then  a  zone  of  bluish- white,  and  a  patch  of 
brown  just  beneath  the  apex. 

Genus  Lottia 

i.  gigantea.  This  is  the  largest  of  the  California  limpets.  Specimens 
three  inches  long  have  been  found.  The  outer  surface  of  the  shell  is 
rough  and  brownish  in  color.  The  apex  is  near  one  end.  Within  it  is 
almost  black,  shining,  lustrous,  with  a  horseshoe-shaped  muscle-scar 
under  the  apex.    The  color  is  bluish  and  brown.     (Plate  LXY.) 


Family  fissueellid^ 

This  is  an  extensive  family,  including  several  genera  and  a 
number  of  species,  commonly  knov^n  as  keyhole-limpets.  In 
the  general  form  of  the  shell  they  closely  resemble  the  true 
limpets,  the  AcmceidcB,  except  that  they  have  a  hole,  or  rather  a 
slit,  in  the  shell  just  back  of  the  apex.  Often  this  slit  is  so  long 
that  it  has  entirely  removed  the  apex  of  the  conical  shell. 

Genus  Fissurella 

F,  alternata,  F.  barbadensis.  These  species  occur  upon  the  south- 
ern shores  of  the  United  States,  the  latter,  however,  being  confined  to 


358  MARINE  INVERTEBRATES 

extreme  southern  Florida.  F.  barhadensis  has  heavy  longitudinal  ribs  and 
is  light  green  within,  with  a  rosy  circle  about  the  apical  perforation. 
(Plate  LXV.) 

Genus  Glyphis 

6r.  aspersa.  One  of  the  numerous  species  belonging  to  this  family 
which  are  found  on  the  west  coast  of  the  United  States.  It  is  about  one 
and  a  half  inches  long,  grajdsh- white,  with  sharply  raised  longitudinal 
ridges,  slightly  rayed,  crossed  by  revolving  ribs,  which  give  to  the 
outer  surface  a  decussated  appearance.  The  apex  is  forward  of  the 
center,  and  is  entirely  replaced  by  a  round  perforation.  The  edge  is 
wrinkled,  and  within  smooth  and  white. 

Genus  Lucapina 

L*  crenulata.  The  largest  of  the  keyhole -limpets  ',  the  shell  is  often 
four  inches  in  length,  while  the  animal,  with  its  huge  yellowish  foot  and 
dark-colored  mantle,  which  is  thrown  back,  almost  concealing  the  shell 
upon  its  back,  is  much  larger.  The  apical  perforation  is  very  large.  Shell 
flattened,  with  radiating,  rounded,  crowded  ribs;  brownish-white  in 
color )  edge  crenulated ;  within  pure  white.  It  is  found  at  Monterey,  but 
live  specimens  are  not  very  frequently  seen  near  the  beach.  (Plate 
LXVI.) 

Family  haliotid^ 

Genus  Haliotis 

This  family  is  closely  allied  to  the  FisstireUidce.  The  species  are 
known  on  the  Pacific  coast  by  the  name  of  abalone  shells,  and  in 
England  and  the  Channel  Islands  as  ormers  or  sea-ears.  There 
are  no  species  of  Haliotis  on  the  east  coast  of  the  United  States, 
but  one  has  recently  been  dredged  at  a  considerable  depth  in  West 
Indian  waters.  This  family,  with  the  last,  possesses  the  striking 
anatomical  feature  of  having  the  heart  traversed  by  the  digestive 
tract.  It  also  has  two  gills,  the  degree  of  torsion  in  the  visceral 
mass  not  being  sufficient  to  have  crowded  out  and  destroyed  the 
original  right  gill.  The  shell  is  spiral,  but  is  so  greatly  flattened, 
and  the  body- whorl  is  so  greatly  extended,  that  the  shell  quite 
loses  the  spiral  appearance.  Along  the  dorsal  side  of  the  shell  is 
a  row  of  holes,  through  which  project  numerous  tentacular  pro- 
cesses from  the  mantle.  The  outer  surface  of  the  shell,  before  it  is 
polished,  is  usually  rough  and  unattractive,  but  within,  when  the 


GASTEROPODS  359 

animal  is  removed,  it  displays  a  most  beautiful  and  higlily  colored 
nacreous  surface.  The  spot  near  the  center  of  the  inner  shell 
surface  where  the  muscles  of  the  foot  were  attached  is  usually 
most  brilliantly  colored.  The  shell  of  the  abalone  is  susceptible 
of  taking  a  very  high  degree  of  polish,  and  is  extensively  used  in 
commerce  for  colored  mother-of-pearl  and  for  inlaid  work.  Hal- 
iotis  is  a  vegetable-feeding  genus.  They  cling  with  great  tenacity 
to  rocks  about  low  tide,  and  it  requires  skill  to  remove  them  with- 
out breaking  the  shell.  There  are  several  species  in  California. 
The  Chinese  use  the  abalone  for  food,  and  have  waged  a  persis- 
tent war  upon  the  family  along  the  Pacific  coast  until  the  speci- 
mens are  not  nearly  as  common  as  formerly.  They  are  also  eaten 
in  France  and  in  Japan. 

H.  splendetis.  The  largest  and  perhaps  the  most  attractive  in 
appearance  of  the  Calif ornian  species.  Speaking  of  this  beautiful  shell, 
Professor  Keep  says  :  "  Within,  a  whole  rainbow  is  condensed  in  one  of 
the  magnificent  shells,  though  the  shades  of  green  are  most  conspicuous. 
The  coloring  in  the  center  is  particularly  fine,  resembling  a  peacock's 
tail.  There  are  about  six  open  holes  near  one  side  of  the  shell,  and  its 
length  is  about  the  same  number  of  inches."     (Plate  LXVI.) 

H.  rufescens.  A  large  abalone,  which  sometimes  attains  a  length  of 
eight  or  nine  inches.  It  is  red  in  color,  with  three  open  holes  in  the 
body-whorl.  The  outer  portion  of  the  shell  is  usually  incrusted  with 
mineral  deposit  and  overgrown  with  vegetation. 

H,  cracherodii.  Very  dark  green  without,  with  five  to  nine  holes ; 
length  from  one  to  six  inches ;  spire  exceedingly  short.  Common  on  the 
Cahfornian  coast  in  crevices  of  rocks  at  low  tide. 

Family  trochid^ 

This  is  one  of  the  largest  and  most  interesting  families  of  the 
Molhisca.  It  contains  many  apparently  widely  separated  genera 
and  a  host  of  species,  which  for  the  most  part  are  littoral,  the 
majority  actually  living  between  tide-marks.  The  typical  trochid 
shell  is  top-shaped  or  pyramidal,  having  a  broad  base  and  many 
closely  wound  flat  whorls  terminating  in  a  sharp  apex.  All  the 
trochids  are  nacreous  within  the  aperture— a  character  which  is 
constant  throughout  the  family.  The  animal  has  but  one  gill 
(the  left),  a  short  snout,  and  often  frontal  lobes  on  the  head. 
The  edge  of  the  mantle  or  the  epipodial  line  of  the  foot  is  usually 
ornamented  with  from  three  to   five   cirri.     The  tentacles   are 


360  MARINE  INVERTEBRATES 

long  and  slender,  with  short  peduncles  for  the  eyes ;  the  opercu- 
lum is  corneous,  with  a  central  nucleus.  The  animals  are  herbiv- 
orous, feeding  upon  algse.  The  trochids  are  essentially  tropical 
shells,  and  the  most  of  the  genera  which  are  comprised  in  the 
family  are  only  to  be  encountered  in  the  warm  waters  of  the 
Pacific  and  Indian  oceans.  Some  forms  are  very  beautiful,  and 
frequently  are  used  as  mantel  ornaments,  and  the  shells  of  one 
little  species,  which  is  opalescent  in  its  coloring,  are  still  exten- 
sively gathered  in  the  East  Indies,  to  be  polished  and  strung  like 
pearls  in  necklaces. 

Genus  Margarita 

On  the  Atlantic  coast  north  of  Cape  Cod  the  trochids  are  rep- 
resented by  the  genus  Margarita,  with  five  or  six  species.  The 
shells  are  small,  thin,  and  globosely  depressed,  with  smooth  or 
transversely  striated  whorls.  The  aperture  is  nearly  circular, 
with  a  simple  lip. 

M.  cinerea.    This  species  has  several  prominent  revolving  ridges 
upon  the  upper  side  of  the  whorls,  with  finer  ones  on  the  base.     Very 
fine  growth-lines  cover  the  entire  shell.     It  ranges  all  along 
the  coast  north  of  Cape  Cod,  but  is  not  usually  found  between 
tides.     The  writer  has  dredged  many  specimens  in  shallow 
water  at  Eastport  and  Bar  Harbor. 
M,  heliclna,    A  thinner  and  more  globose  species  than  the 
^'cineret'    "^^^^J  "^^^^  ^  trausluceut,  shining,  smooth  surface  of  a  yellow- 
ish or  olive  color.     M.  lielicina  is  very  fond  of  the  leaves  of 
Laminaria,  and  is  often  found  clinging  to  them  when 
storms  have  torn  these  great  algae  from  the  bottom  and    Jts^^^ 
cast  them  upon  the  shore.     At  Bar  Harbor  they  are  com-    ^^^^!^  •— l""^ 
mon  upon  the  eel-grass  in  Rodicks  Weir.    This  species  can    ^^^B-y     i- 
generally  be  distinguishedby  its  iridescent,  metallic  luster.    ,,        .,  ,  ,.  . 

71/*-  ^     1    J.  A  •  1  n  Margarita  helicma. 

M,  unaiUata,  A  commoner  species,  perhaps,  than 
either  of  the  preceding,  sometimes  found  on  the  rocks  of  sheltered 
coves  at  exceptionally  low  tides.  Judging  from,  the  number 
often  to  be  fouud  in  the  stomachs  of  fishes,  they  must  be  con- 
sidered excellent  food  by  the  cod  and  its  aUied  species  which 
thrive  along  the  Maine  coast.  No  doubt  millions  of  M.  undulata 
^unduZtT  ^^'^  y^^i^ly  destroyed  in  this  way.  The  shell  is  depressed, 
with  four  rounded  whorls,  a  flattish  base,  and  a  large  umbilical 
opening.  In  color  it  varies  from  rose-red  to  brown.  The  surface  is  deco- 
rated with  numerous  revolving  raised  lines  placed  at  uniform  distances. 
Just  below  the  suture  the  body -whorl  is  somewhat  undulated  with  short 
folds.    Height  three  tenths  of  an  inch,  base  four  tenths  of  an  inch. 


GASTEROPODS  361 

Genus  Calliostoma 

This  genus  is  better  represented  on  the  Pacific  coast  of  the 
United  States  than  upon  the  Atlantic.  It  comprises  a  series  of 
marvelously  beautiful  shells,  often  exquisitely  colored.  They 
are  regularly  conical  or  pyramidal  in  shape,  with  flattened  bases. 
One  never  tires  in  the  search  for  calliostomas.  They  are  not  com- 
mon enough  to  cause  one  to  lose  interest,  and  whenever  a  good 
specimen  is  captured  it  seems  as  though  one  had  found  some  gem 
cut  and  polished  by  nature's  skilful  hand  and  prepared  for  a 
place  of  honor  in  the  cabinet. 

C.  occiclentale.  The  only  species  of  this  genus  found  on  the  north- 
east coast.  It  is  larger  than  Margarita  cinerea,  but  somewhat  resembles 
it.  It  is  shining  nacreous  within  and  without,  and  has  strong 
revolving  ribs,  the  upper  one  on  each  whorl  often  being 
broken  into  a  cu'cular  row  of  white  dots.  The  lip  is  crenu- 
lated.  This  very  pretty  species  is  not  likely  to  be  met  with 
upon  the  shore,  but  may  be  dredged  in  shallow  water  on 
gravelly  bottoms  along  the  Maine  coast.  Height  about 
one  half  of  an  inch. 

C.  jujubiniim,  A  species  which  occurs  in  the  waters  of  Florida. 
Its  form  is  almost  that  of  a  true  pyramid.  The  sutures  can  scarcely  be 
distinguished.  The  shell  is  marked  by  brown  and  purplish-red  spots  on 
a  white  background,  and  has  numeroiis  revolving  ribs  broken  into  rows 
of  white  dots  like  little  glazed  beads.  The  umbilicus  is  funnel-shaped 
and  wide.  In  Tampa  Bay  this  shell  is  frequently  found  on  sponges,  and 
may  sometimes  be  gathered  on  the  beach  after  storms,  even  as  far  north 
as  Hatteras.  There  are  as  many  as  twenty  species  of  this  genus  in  Ameri- 
can Atlantic  waters,  but  they  are  either  rare  or  have  deep-water  stations. 

C,  anmilatuin,  A  remarkable  species  of  Calliostoma,  found  in  Cal- 
ifornia. The  whorls  are  adorned  with  revolving  rows  of  raised  dots,  and 
the  sutures  are  frescoed  in  exquisite  purple.  This  beautif  al  species  lives 
upon  seaweed,  and  on  pleasant  days  comes  to  the  surface  of  the  water. 
It  can  then  be  collected  from  a  boat  by  drawing  in  quantities  of  sea- 
weed. It  is  very  unhkely  that  the  collector  wiU  ever  find  a  specimen 
upon  the  beach,  for  the  shell  is  too  fragile  to  withstand  the  rough  han- 
dling of  the  waves.     Length  one  inch. 

C  canaliculatiim.  The  largest  member  of  this  genus  to  be  found 
in  American  waters.  It  resembles  the  last  species  in  form,  but  lacks  the 
purple  sutures.  The  revolving  ribs  are  very  numerous  and  prominent. 
There  is  no  umbilicus.  Length  one  to  one  and  a  half  inches.  Found  on 
the  Pacific  coast. 

C.  costatuni,  A  heavier  shell  than  the  preceding,  with  somewhat 
more  rounded  whorls.  Reddish-brown  in  color  j  numerous  revolving 
ridges ;  no  umbilicus ;  about  three  quarters  of  an  inch  in  length.  It  is 
found  in  rocky  places,  and  sometimes  in  considerable  numbers,  just  at 
low-tide  mark.     Found  in  California. 


362  MARINE  INVERTEBRATES 

Genus  Chlorostoma 
This  genus  is  represented  in  California  by  several  species,  the 
commonest  of  which  is  probably  (7.  funeby^ale—d^  doleful  name,  no 
doubt  given  on  account  of  the  jet-black  color. 

C  funebrale.  The  shell  is  thick  and  strong,  like  most  between-tide 
species,  which  are  constantly  exposed  to  the  buffeting  of  the  waves.  It 
is  to  be  found  in  countless  thousands  upon  rocks  exposed  at  low  tide, 
and  may  be  gathered  at  any  time  except  full  flood-tide,  like  the  Httorinas 
and  purpuras  of  the  east  coast.  Within  the  aperture  the  sui'face  is 
nacreous  and  greenish  in  tint ;  the  last  whorl  is  drawn  in,  like  gathers, 
at  the  suture.  The  umbilicus  is  closed.  There  is  a  white  nodule  at  the 
base  of  the  lip  of  the  columella.  Length  one  half  of  an  inch  to  one  inch. 
(Plate  LXVIL) 

C  bi'unneutn.  This  species  is  brown,  as  its  name  would  indicate, 
and  there  is  greenish  nacre  within  the  aperture.  It  lives  upon  kelp,  or 
upon  rocks  at  very  low  tide.     Length  about  an  inch.     (Plate  LXVI. ) 

'    Genus  Trochiscus 

T,  norrisi,  A  flattened  shell  with  rounded,  dome-like  spire  and 
obtuse  apex;  a  fairly  common  species.  It  has  a  wide,  deep  umbilicus 
and  a  sharp  lip.  It  is  of  a  rich  brown  color,  with  dark  chestnut  about 
the  umbilical  region  and  greenish- white  within  the  umbilicus ;  there  is 
a  band  of  dark  olive-green  about  the  inner  margin  of  the  lip.  The  shell 
is  about  two  inches  in  diameter  and  of  a  somewhat  greater  height.  The 
operculum  is  multispiral,  with  a  central  nucleus,  and  is  shaggy  and 
rough.  Like  all  other  trochids,  it  feeds  upon  algse.  It  is  often  found 
upon  the  beach  after  violent  storms.  Found  in  California,  south  of  San 
Francisco.     (Plate  LXVI.) 

Genus  Livona 

L,  pica.  This  large  and  interesting  trochid  is  a  West  Indian  species 
which  sometimes  occurs  in  Florida.  It  lives  about  coral  reefs  and  rocky 
shores,  attaching  itself  in  vast  numbers  to  the  rocks.  This  shell  is  a 
favorite  refuge  for  large  hermit-crabs.  It  is  a  curious  sight  in  certain 
of  the  West  India  islands  to  see  a  Livona  pica  shell  scrambling  up  a  tree, 
looking  very  much  out  of  place  upon  the  back  of  some  terrestrially  in- 
clined crustacean.  When  well  cleaned  it  is  a  beautiful  shell,  with  black 
wavy  lines  over  a  greenish-white  nacreous  f  dation.  The  animal  has 
a  row  of  waving  cirri  upon  each  side  of  %e  mantle,  and  long,  slender 
tentacles.  It  is  largely  used  as  an  article  of  diet  in  the  West  Indies  and 
Central  America.     (Plate  LXVIL) 

i 
Family  turbinidje 

This  family  is  very  closely  allied  to  the  trochids,  the  most 
striking  difference  being  in  the  operculum,  which  in  the  TurUnidce 
is  calcareous  and  usually  smooth  and  very  convex  on  the  outside. 


PLATE    LXVI. 


1,  Lucapina  crenulata.  3,  Chlorostoma  brunneum. 

2,  Haliotis  splendens.  4,  Neritina  reclivata,  enlarged. 

5,  Trochiscus  norrisi. 


PLATE  LXVII. 


Livona  pica,  reduced. 
Nerita  peleronta. 
Nerita  tessellata. 


Turbo  castaneus,  enlarged. 
Chlorostoma  funebrale. 


GASTEROPODS  363 

The  shells  are  nacreous  within,  and  the  animal,  with  its  rows  of 
waving  cirri  upon  each  side,  is  very  suggestive  of  Trochus. 
They  are,  for  the  most  part,  shallow-water  or  littoral  forms. 

Genus  Turbo 

T,  castaneus.  This  species  has  a  range  as  far  north  as  Cape  Hatteras, 
and  is  especially  abundant  at  Tampa,  on  the  west  coast  of  Florida.  The 
pecuhar  operculum  is  sufficient  to  identify  the  genus  at  once.  One 
variety  of  this  species  has  a  crenulated  shoulder  upon  the  body-whorl 
and  is  referred  to  as  Turbo  crenulatus,  A  series  of  intermediate 
forms  establishes  the  specific  identity  of  the  two  varieties.    (Plate  LXVII. ) 

Family  neritid^ 
The  NeritidcB  are  strictly  littoral  forms,  almost  entirely  confined 
to  the  warmer  waters  of  tropical  seas.  The  animal  preserves  the 
usual  diatocardian  features — has  a  short  snout  and  long  tenta- 
cles. Unlike  the  trochids  and  Titrho,  it  has  no  cirri  along  the 
epipodial  margin.  The  shells  are  peculiarly  shaped,  the  spire 
being  greatly  flattened  and  scarcely  noticeable  on  account  of  the 
unduly  large  development  of  the  body- whorl ;  thus  the  shell  takes 
on  a  decidedly  patelliform  appearance.  It  is  without  an  umbilicus. 
In  the  principal  genus  Nerita  the  outer  lip  is  sharp  on  the  edge, 
but  greatly  thickened  just  within. 

(xENus  Werita 

N,  peleronta.  This  shell  has  two  teeth  on  the  wide,  flat  columellar 
lip,  and  about  them  is  a  blotch  of  red,  suggesting  blood.  The  common 
name  of  this  shell,  "bleeding-tooth,"  is  very  appropriate.  Found  in 
southern  Florida.     (Plate  LXVII.) 

N,  tessellata  is  a  smaller  species,  with  heavy  revolving  ribs,  and  is 
further  decorated  with  transverse  oblique  black  lines.  The  operculum 
is  calcareous.  Both  of  these  species  have  the  habit  of  absorbing  the 
entire  inner  portion  of  their  shells.  They  belong  to  the  West  Indian 
fauna,  and  occur  in  great  numbers  on  rocky  or  coral  shore  stations. 
They  also  may  be  found  on  the  east  Florida  coast,  well  to  the  south. 
A  third  species,  N',  versicolor,  often  occurs,  associated  with  the  other 
two.  It  is  somewhat  smaller  than  the  others  and  can  easily  be  distin- 
guished by  the  four  teeth  on  the  columellar  lip,  the  edge  of  the 
columella  being  convex.     (Plate  LXVII. ) 

Genus  Neritina 

The  genus  Neritina  is  very  closely  allied  to  the  last,  having 
quite  the  same  form  of  shell ;  but  it  is  usually  more  globular  and 


364  MARINE  INVERTEBRATES 

variously  ornamented  by  bright  spots  or  zigzag  lines  of  colora- 
tion. The  neritinas  have  acquired  the  habit  of  ascending  rivers, 
until  they  have  become  almost  wholly  a  brackish-  or  fresh-water 
genus.  The  metropolis  of  this  genus  is  in  the  South  Sea  Islands, 
where  it  attains  a  wonderful  development  in  the  clear  running 
streams  of  the  volcanic  islands. 

JV.  reclivata.  A  very  pretty  olive-green  species,  with  very  fine,  wavy, 
longitudinal  lines  of  coloration,  found  in  almost  all  Floridian  streams 
above  the  action  of  the  tide.  The  nacre  of  the  columella  and  within 
the  aperture  is  bluish-green,  and  the  operculum  is  rich  oHve.  (Plate 
LXVI.) 

N,  viridis,  A  smaU,  intensely  green  species,  which,  unlike  most 
neritinas,  is  strictly  marine.  It  belongs  to  the  great  West  Indian  faunal 
province,  but  is  occasionally  found  upon  the  shores  of  Florida  and  of 
Texas. 

The  prosobranch  gasteropods  thus  far  considered  (belonging  to 
the  suborder  JDiatocardia)  all  show  by  their  anatomical  structure 
that  the  process  of  visceral  torsion,  though  carried  very  far  within 
them,  has  not  been  complete  enough  to  crowd  out  and  finally 
destroy  one  of  each  of  the  paired  organs.  Both  auricles  of  the 
heart  (with  some  exceptions)  were  left  intact. 

Suborder  monotocardia 

In  this  the  second  suborder  of  the  prosobranch  gasteropods, 
the  twisting  visceral  process  has  been  carried  to  the  extreme. 
The  heart  has  but  one  auricle.  There  is  but  one  gill  (on  the  left 
side),  and  this  is  attached  to  the  inner  side  of  the  mantle  flap. 
In  other  respects  the  presence  of  certain  specialized  organs  would 
probably  indicate  that  gasteropods  belonging  to  this  suborder 
are  a  step  higher  in  the  scale  of  life  than  those  which  belong  to 
the  Diatocardia. 

Family  janthinidje 

Genus  Janthina 

The  genus  Janthina  has  an  exceedingly  thin  and  semi-trans- 
parent shell,  deep  violet  in  color  on  the  base  and  lighter  blue  on 
the  spire.  An  interesting  feature  of  this  genus  is  the  mode  of  de- 
positing the  ova.     The  female  exudes  from  a  gland  in  the  foot  a 


> 


GASTEROPODS 


365 


glutinous  secretion  which  hardens  in  water,  and,  being  filled  with 
air-bubbles,  constitutes  a  float.  On  the  under  side  of  this  are 
deposited  the  eggs  in  rows  of  little  capsules.  While  attached  to 
this  float  it  is  impossible  for  a  Jantliina  to  sink,  and  hence  it  is 
that  so  many  of  these  creatures  are  sacrificed  in  onshore  gales  of 
wind. 

J,  fragilis.  The  shell  of  this  species  is  so  brittle  and  fragile  that  it 
is  very  clearly  not  adapted  to  a  life  near  shore.  It  is  in  reality  a  pelagic 
species  which  is  occasionally  blown  ashore  during  easterly  gales  along 


Jantliina  fragilis :  FL,  float ;  O,  ova ;  Pr,  proboscis  ;  Br,  branchiae  ;  F,  foot. 

the  Atlantic  coast  of  the  United  States.  Vast  numbers  of  these  pretty 
creatures  are  sometimes  encountered  far  out  at  sea,  floating  quietly  on 
the  surface.  When  storms  drive  them  upon  the  beach,  they  become 
utterly  helpless  -,  since  their  foot  is  not  adapted  for  crawling  upon  the 
sand,  they  soon  perish,  and  their  brittle  shells  are  demolished  by  the 
surf.  In  Florida  the  beaches  are  sometimes  fairly  lined  with  Janthina 
shells,  which  make  a  band  of  purple  along  the  high-tide  mark  as  far  as 
the  eye  can  reach:  then  it  may  be  years  before  they  again  appear. 
(Plate  LXVIII.) 

Family  scALiD.ffi: 
Genus  Scala 

The  shells  of  Sccda  have  such  a  peculiar  scheme  of  decoration 
that  once  seen  they  can  never  be  mistaken.  They  are  generally 
pure  white,  with  well-rounded  whorls,  all  of  which  are  crossed  at 
even  distances  by  greatly  elevated  and  smooth  ribs.  Each  rib 
represents  a  rest-period,  when  the  creature  thickened  the  rim  of 
the  shell-aperture.  The  aperture  is  generally  round,  with  a  con- 
tinuous lip.  The  animal  has  a  retractile  proboscis  and  long, 
slender  tentacles  with  eyes  at  the  outer  bases,  and  is  a  predaceous, 
carnivorous  creature.     Some  Asiatic  species  of  this  genus,  remark- 


366 


MARINE  INVERTEBRATES 


able  for  their  beauty  and  rarity^  have  been  greatly  prized  by  col- 
lectors. A  single  specimen  of  the  now  well-known  S,  iwetiosa  of 
China  has  been  sold  for  two  hundred  dollars— a  fancy  price,  indeed, 
for  a  shell  which  can  now  be  bought  for  a  dollar !  There  are 
over  fifty  species  of  Scala  on  the  Atlantic  coast,  but  most  of  them 
are  either  rare  or  belong  to  a  zone  of  deeper  water;  there  are, 
however,  four  or  five  species  which  are  exceedingly  common. 

S.  lineata,  A  species  which  ranges  from  Hatteras  to  New 
England.  It  has  about  eight  whorls,  and  is  slightly  brownish 
in  color.  The  ribs  are  robust  and  not  greatly  elevated ;  there 
are  from  seventeen  to  nineteen  on  the  body- whorl.  The  shell 
is  sometimes  painted  with  a  few  revolving  brownish  hues. 

S,  tnultistriata.     The  transverse  ribs  are  much  smaller  but 
very  numerous ;  the  small  spaces  between  them  are 
marked  with  many  fine  revolving  lines.     Found 
from  Cape  Cod  southward. 

S,  groenlandica.   Essentially  an  arctic  species, 
which  has  found  its  way  down  to  the  New  England 
coast.     It  is  readily  distinguished  by  the  flattened^ 
coarsely   rounded,   revolving   ribs,   which   follow 
the  volutions   of  the  spire.      Over  them  are  the  usual  trans- 
verse heavy  ribs  peculiar  to  this  genus. 

S,  angulata.      The  whorls  touch  one  another  only  by  the 
ribs,  of  which  there  are  nine  to  each  volution.     This  species    g^aia  muitistri- 
has  a  remarkably  wide  range,  occurring  from  Cape  ata. 

Cod  to  southern  Florida.     (Plate  LXVIII,) 

These  four  species  vary  from  one  half  of  an  inch  to  one  inch 
in  length.  All  of  them  are  found  on  the  beach  after  storms  or 
may  be  dredged  in  shallow  water  near  the  shore. 

Family  naticid^ 

This  large  and  interesting  family  is  well  represented 
in  the  Atlantic  waters  of  the  United  States,  but  its  more 
beautiful  members  live  in  the  tropics.  The  New  England 
and  New  Jersey  species  are  dull  in  color,  but  offer  much  of  interest 
to  the  collector  and  student.  The  foot  is  enormously  large,  and 
carries  in  front  a  great  shield-like  fleshy  process,  which  curves  back 
over  the  head  of  the  animal  and  serves  as  a  plow  in  pushing  its  way 
through  the  heavy  wet  sand  of  the  beach.  When  the  creature  is 
thus  seen  extended  in  the  act  of  crawling,  one  wonders  how  it  is  pos- 
sible for  it  to  withdraw  so  great  an  amount  of  body  into  its  shell ; 
but  if  it  is  suddenly  seized  or  irritated,  it  will  quickly  demon- 


Scala  groen 
landica. 


PLATE  LXVIII. 


Janthina  fragilis. 

Scala  angulata,  enlarged. 

Natica  canrena. 


Sigaretus  perspectivus,  upper  side. 
Sigaretus  perspectivus,  under  side. 
Crepidula  aculeata. 


GASTEROPODS  367 

strate  its  ability  to  hide  itself  completely  within  its  house  and  to 
close  the  door  very  effectively  by  means  of  its  operculum.  The 
eyes  seem  to  be  wanting,  or  they  are  concealed  under  the  skin 
of  the  head.  The  shell  is  usually  quite  large,  with  a  depressed 
spire  and  well-rounded  whorls — especially  the  body- whorl,  which 
appears  to  be  greatly  swollen.  The  umbilicus  is  usually  open  and 
moderately  large,  the  lip  simple. 

Genus  Polynices  (Lunatiaf  Natica), 

P,  /i^c^os' (generally  referred  to  as  Lunatia  or  Natica  heros).    One 

of  the  commonest  large  shells  and  one  of  the  most  characteristic  species 
of  the  New  England  and  New  Jersey  littoral  fauna.  It  is  exceedingly 
common  along  the  Long  Island  shore,  where  it  may  be  found  on  the 
open  beach,  in  pools  with  a  sandy  bottom  left  by  the  receding  tide.  It  is 
usually  partially  and  frequently  wholly  buried  in  the  sand.  The  umbili- 
cus is  open  and  large,  the  operculum  corneous,  and  the  shell  heavy  and 
ashy-white  to  brownish,  with  (when  young)  a  yellowish  epidermis.  Its 
length  is  from  two  to  four  inches.  It  has  no  ornamentation  whatever.  P. 
hews  is  a  most  voracious  creature  and  spends  its  time  in  hunting  for 
flesh  —  either  alive  or  dead  —  to  devour.  It  feeds  upon  dead  fish,  or 
upon  other  mollusks  whose  shell  it  is  able  to  pierce  by  means  of  its 
radula,  making  a  little  round  hole  through  which  it  sucks  out  the  flesh 
from  within.  The  curious  egg-cases  of  this  species  have  already  been 
referred  to.  (See  Plate  I.)  It  glues  together  particles  of  sand  into  the 
form  of  a  basin  with  the  bottom  knocked  out  and  broken  on  one  side. 
In  the  gelatinous  substance  of  this  basin  it  deposits  its  eggs  in  a  regular 
order.  These  hatch  out  in  midsummer.  Egg-cases  of  this  kind  can 
always  be  found  wherever  Polynices  lives.  For  a  long  time  naturalists 
were  greatly  puzzled  by  these  curious  things,  and  their  blunders  are 
recorded  in  earlier  works,  where  these  egg-cases  have  been  elaborately 
described  as  living  animals  belonging  to  various  invertebrate  orders. 
The  largest  and  best  specimens  of  P.  Jieros  are  to  be  found  south  of 
Cape  Cod.     (Page  343.) 

P,  triseriata.  A  small  shell  of  exactly  the  same  shape  as  P.  heros, 
but  decorated  with  three  revolving  series  of  bluish  or  chestnut  spots. 
It  is  pretty  well  determined  that  this  so-called 
species  is  only  the  young  of  P.  heros.  It  is  very 
abundant  all  along  the  coast. 

J*.  dupUcata,  This  is  even  more  abundant 
than  P.  heros.  It  has  a  flatter  shell,  with  an  obtuse 
apex  and  dome-hke  spire.  The  umbihcus  is 
partly  or  wholly  closed  by  a  thick,  callous,  sheUy 

process  thrown   off  from  the  Columellar  lip,  and  is       Polynices  triseriata,  yo-ang -, 

chestnut  in  color.  The  surface  of  the  shell  is  f^^Sen  '"'''''''''''  ''^^^'' 
smooth,  often  polished,  ashy- white  below  and  light 

chestnut  above.  The  operculum  is  corneous.  The  length  of  the  shell 
varies  in   different  localities  from  one   half  of  an  inch  to  about  two 


368 


MABINE  INVERTEBRATES 


Northern 
abundant 


Polynices  duplicata. 


inches ;  the  breadth  slightly  exceeds  the  length.    P.  duplicata  has  a  very 
extensive   range,   from   the  Gulf  of  Mexico  to   Newfoundland.      The 

largest  and  finest  specimens  are 
found  in  the  vicinity  of  New  York 
and  at  Hatteras.  In  Florida  they 
are  usually  smaller.  This  species 
cannot  be  confounded  with  any 
other  upon  our  coast  on  accou 
the  heavy  callous  deposit  over\^he 
umbilicus.  Its  habits  are  simi 
to  those  of  P.  heros. 

Natica  claiisa,  A 
species  which  is  fairly 
on  the  Maine  coast.  It 
has  a  shelly  operculum, 
and  the  umbilicus  is 
neatly  closed  by  a  pure 
white,  shining  callosity. 
Its  length  is  about  one 
half  an  inch,  its  color 
livid  white  to  light  brown , 
white  within.  The  calcareous  operculum  at  once  determines  this  shell. 
This  species  (as  well  as  the  following  one)  has  retained  the  generic 
name  of  Natica  because  of  the  shelly  operculum,  as  explained 
below. 

N,  canrena.  One  of  the  handsomer  species  of  Natica,  which  occurs 
m  Florida.  Sometimes  it  is  seen  as  far  north  as  Hatteras.  The  shell  is 
white,  with  bars  of  light  chestnut  circling  the  whorls,  and  with  zigzag 
lines  of  darker  purplish  hue  crossing  them.  The  base  of  the  shell  is 
white.  The  aperture  is  large  and  flaring,  and  is  purplish  within.  The 
umbilicus  is  partially  closed  by  an  entering  callous  plug.  The  operculum 
is  calcareous,  with  eccentric,  deeply  cut  grooves.  Found  in  sandy  sta- 
tions just  about  low-water  mark.     (Plate  LXVIII.) 

PL  leivisii,  A  species  which  occurs  on  the  west  coast  of  the  United 
States.  It  resembles  its  New  England  relative  P.  heros  very  closely.  P. 
leivisii  is  a  Northern  species,  and  does  not  range  south  of  Oregon.  Pro- 
fessor Keep  mentions  one  specimen  of  the  size  of  a  six-inch  globe,  but 
such  dimensions  are  very  unusual.  A  good-sized  specimen  need  not 
exceed  four  inches  in  height. 

JP,  recluziana,  A  species  well  known  on  the  southern  coast  of  Cali- 
fornia. The  umbilicus  is  closed  by  a  thick,  highly  polished  white  cal- 
losity, and  the  general  shape  of  the  shell  is  strongly  suggestive  of  the 
common  east-coast  species  P.  duplicata.  A  large  specimen  is  about  two 
inches  in  diameter. 

[There  has  been  much  confusion  in  the  generic  nomenclature  of  this 
family.  The  old  name  Natica  once  did  service  for  all  the  species ;  then 
the  names  Lunatia,  Neverita,  and  Polynices  were  applied  to  certain  spe- 
cial forms  ;  but  it  has  been  wisely  proposed  by  conchologists  to  use  the 
name  Natica  for  those  forms  having  a  shelly  operculum,  and  to  adopt  the 
name  Polynices  for  those  having  a  corneous  operculum.  Lunatia  and 
Neverita  have  become  subgenera  of  Polynices.] 


GASTEROPODS 


369 


Genus  Sigaretus 

A  very  interesting  species  of  tliis  genus  occurs  on  the  east 
coastj  sparingly  in  New  Jersey,  but  very  abundantly  south  of 
Hatteras.  Sigaretus  is  a  modified  Natica.  The  spire  is  flattened 
and  minute.  The  body-whorl,  being  greatly  expanded,  gives  a 
wide,  flaring,  oblique  aperture.  The  shell  is  ear-shaped  and  white, 
with  fine  revolving  lines.  There  is  no  umbilicus.  The  operculum 
is  small  and  rudimentary.  The  animal  is  large,  with  an  enormous 
foot  and  greatly  developed  propodium,  and  is  a  sand-dweller. 
The  common  east-coast  form  is  S,  perspectivus,     (Plate  LXVIII.) 


FaIVIILY  CAPULID.E 

Genus  Crepidiila 

C.  fornicata.  All  collectors  of  uiollusks  on  the  Atlantic  coast  sooner 
or  later  encounter  this  exceedingly  common  species  adhering  to  oyster- 
shells  or  scallops,  and  often  to  other  large  live  shells. 
It  is  cast  upon  the  beach  along  the  entire  length 
of  the  Atlantic  coast.  The  shell  is  obliquely  oval, 
dull  whitish  in  color,  and  either  smooth  or  rough 
or  even  ribbed,  according  to  the  nature  of  the  sur- 
face to  which  it  clings.  The  spire  is  almost  entirely 
suppressed,  the  little  inconspicuous  apex  being 
turned  to  one  side  and  closely  pressed  down  against 
the  body  of  the  shell.  When  looking  into  the  in- 
terior of  the  shell  one  is  reminded  of  a  boat,  for  the 
upper  portion  of  the  aperture  is  covered  by  a 
horizontal  shelly  partition,  caUed  the  diaphragm, 
a  space  being  left  below  which  would  correspond 

to  the   forecastle    of  a   ship.      The  ^^stem"  is  round, 
and  the  ''  bow  "  is  suggestively  pointed. 

C  plana.  In  this  species  the  shell  is  white  and  flat, 
or  slightly  concave.  Although  it  is  pointed  at  the  ' '  bow  " 
end  and  square  at  the  "  stern,"  the  nautical  resemblance 
stops  there,  because,  being  flat,  there  are  no  swelhng 
sides  and  bow.  The  diaphragm  is  about  one  half  the 
length  of  the  shell,  convex,  shining,  white,  and  trans- 
lucent. C.  plana  hves  generally  within  the  aperture  of 
large  dead  shells.  It  has  a  wide  range,  from  Maine  to 
Florida. 

C.  aculeata,  A  common  Floridian  species  which  has 
a  remarkable  range,  being  found  in  nearly  all  the  tropical  and  semi- 
tropical  waters  of  the  world.  It  is  smaller  than  C.  fornicata,  is  reddish- 
brown  with  a  white  diaphragm,  and  has  several  radiating  ribs  on  the 
back,  which  are  inclined  to  be  nodulous.     (Plate  LXVIII. ) 

24 


C'repidulafuraicata. 


Crepidula  plana. 


370  MARINE  INVERTEBRATES 

On  the  Pacific  coast  the  following  species  are  found:  C.  adunca, 
with  a  strongly  recurved  apex,  and  less  than  one  inch  long ;  O.  rugosa, 
rough,  brown,  with  the  apex  lying  on  the  edge  of  the  shell,  and  one 
inch  in  length;  C,  navicelloides,  almost  identical  with  the  east-coast 
C.  plana.     C.  aculeata  also  appears. 

Genus  Crucibtiltim 

Crucihulimi  has  a  peculiar  rounded  shield-like  form, 
with  a  very  small  apex  on  one  side.     Within  there  is 
swlatamXom    a  cup-shaped  appendage  attached  by  one  side  to  the 
^^''''^'         inner  margin  of  the  shell.     This  latter  feature  at  once 
determines  the  genus. 


O.  striatum.     This  species  has  radiating  riblets,  cut  by 
circular  hues  of  growth.     No  dimension  would  quite  reach 
an  inch.     It  is  a  common  shell  on  the  Atlantic  coast,  and 
crucihuium       will  bc  fouud  adhering  to  stones  and  other  shells,  but  it 
striatum,  from     ^g  j^^^^  strictly  Speaking,  a  littoral  species. 

®  ^^'  C,  spinosu^n.     The  shell  exhibits  a  strong  tendency  to 

spinous  processes  on  its  back.     Found  along  the  southern  part  of  the 
California  shore. 

Family  littorinid^ 

Genus  Littorina 

Littorina  is  probably  the  most  characteristic  genus  of  Northern 
littoral  regions.  Together  with  some  of  its  allied  genera  it  is 
also,  probably,  equally  characteristic  of  various  tropical  lit- 
toral faunas  all  over  the  world.  The  family  comprises  strictly 
between-the-tides  genera  and  species.  Indeed,  it  is  suspected 
that  some  species  of  Littorina  are  making  very  fair  progress 
toward  a  terrestrial  condition,  for  they  actually  live  above  high- 
tide  mark,— even  in  the  branches  of  overhanging  trees,— and 
must  certainly  pass  days  at  a  time  out  of  their  natural  element. 
That  such  a  transformation  is  possible  need  not  for  a  moment  be 
doubted,  for  there  are  many  land  mollusks  to-day  that  give  abun- 
dant evidence  of  having  been  at  some  past  time  aquatic  or  ma- 
rine species.  These  changes  in  nature  are  constantly  going  on, 
and  the  gradual  substitution  of  a  lung  for  a  gill  is  no  very  start- 
ling metamorphosis. 


GASTEROPODS  371 

The  littorinas  fairly  swarm  in  favorable  localities  upon  all 
shore  stations.  In  Maine  and  Massachusetts  the  bold,  rocky 
coast  furnishes  a  home  for  several  species.  Often  the  rocks  at 
low  tide  are  black  with  them ;  the  alg^  that  cling  in  wet  masses 
to  the  exposed  rocks  are  alive  with  them.  One  cannot  walk 
about  in  such  localities  without  crushing  hundreds  of  specimens. 
Sometimes  they  will  be  found  clinging  in  clusters  upon  the  piling 
of  old  wharves,  or  crawling  about  the  bottom  at  or  about  the  low- 
tide  mark.  The  best  specimens  of  Littorina  are  found  in  stations 
where  they  are  bathed  twice  a  day  by  pure,  uncontaminated  sea- 
water;  those  living  near  the  mouths  of  streams,  or  where  the 
water  is  brackish  or  impure,  are  usually  small  and  degenerate. 
They  are  vegetable  feeders,  and  have  received  the  common  name 
of  "periwinkles.''  In  Great  Britain  they  are  used  among  the 
poorer  classes  for  food.  The  animal  has  a  short,  broad  muzzle, 
and  eyes  at  the  outer  bases  of  the  tentacles.  The  foot  is  longi- 
tudinally grooved,  and  there  is  a  rudimentary  siphonal  fold  in  the 
mantle.  The  shells  are  turbinated,  usually  heavy,  few-whorled, 
and  with  a  round  aperture. 

i.  litorea.  This  is  supposed  to  be  an  importation  from  the  Old 
World — to  have  come  over  by  way  of  Iceland  and  Greenland,  and  then 
to  have  migrated  down  the  Labrador  coast.  For  many 
years  Cape  Co'd  formed  a  barrier  to  its  advance,  but 
now  the  species  is  abundant  at  Newport,  and  is  reported 
at  New  York.  It  occurs  on  the  Maine  coast  in  astonish- 
ing numbers,  living  in  vast  colonies  on  the  rocks  exposed 
at  low  tide.  The  shell  is  thick,  imperforate  (no  umbil- 
icus), and  usually  has  flat,  spiral  ribs.  The  columella  is 
broad  and  white ;  the  lip  thin  and  black.  The  general 
color  varies  from  black  to  olive  or  to  dinffvecray — some-     ^.„   .     ,., 

,.  1  -I •   1  mi  1  •  -jt      j_i  Littonna  litorea. 

times  reaaish.      ine   operculum  is  corneous,  with  the 
nucleus  near  the  outer  edge.      Despite  the  variableness  of  this  very 
common  shell  (the  variations  being  chiefly  in  the  height  of  the  spire), 
it  has  certain  unmistakable  characteristics  which,  once  seen, 
will  enable  the  collector  to  determine  it  at  once. 

L,  rudis,  A  smaller  species  than  the  last.  It  is  strong 
and  coarse,  with  revolving  grooves  and  ribs,  or  smooth,  with 
interrupted  whitish  bands  and  spots.  A  very  common  vari- 
ety of  this  species  is  much  smaller  than  the  typical  form, 
being  about  one  sixth  to  one  fourth  of  an  inch  long,  smooth, 
with  white  and  yellowish  spots  on  olive.  It  clings  to  the  rocks 
near  high-tide  mark,  and  is  usually  found  attached  to  its 
resting-place  by  a  bit  of  hardened  mucus.  "While  the  typical  L.  rudis 
is  heavy  and  banded,  with  a  moderately  high  spire  and  no   color,  this 


372  MARINE  INVERTEBRATES 

variety  is  tMnner,  with  a  higher  spire  and  smoother  surface,  and  has  a 
color-scheme  of  decoration.  It  would  be  impossible  to  disconnect  the 
two,  for  a  large  series  of  specimens  will  demonstrate  beyond  doubt, 
through  every  minute  degree  of  variation,  that  the  two  forms  belong  to 
one  and  the  same  species.  The  station  of  L,  rudis  is  much  the  same  as 
that  of  L.  litorea,  but  the  smaller  colored  variety  of  rudis  prefers  quieter 
and  more  sheltered  spots.  It  is  occasionally  found  on  reeds  and  grasses, 
on  the  piling  of  wharves,  on  large  boulders  above  the  line  of  algSB,  and 
on  algae.  It  has  been  the  writer's  experience  not  to  find  mdis  and  litorea 
associated  together. 

L,  palliata,  A  low-spired,  globular  shell  with  a  large,  tumid,  smooth 
body-whorl.  The  columella  is  flattened,  curved  below,  and  imperforate. 
The  color  is  exceedingly  variable,  but  is  usually  bright,  shining  olive, 
and  this  is  especially  the  case  with  those  individuals  that  find 
their  station  in  the  dense  masses  of  algae  that  form  so  conspic- 
uous a  feature  of  a  low-tide  scene  on  a  rocky  New  England 
coast.  From  pure  olive-green  to  yellow  or  bright  red,  with 
revolving  black  bands,  seems  a  long  chromatic  leap,  but  it  is 
^^aiiiata  ^^^  ^^^  great  for  the  Designer  of  these  pretty  little  globular 
pa  laa.  ^-j^eWs.  As  a  rule,  the  color  of  the  shell  simulates  pretty 
closely  that  of  the  seaweed  upon  which  it  lives,  and  inexperienced 
eyes  may  easily  overlook  hundreds  of  specimens,  all  within  close  reach. 
The  banded  varieties  are  less  common.  The  head  of  the  animal  is 
somewhat  orange  in  color,  the  foot  slate.  The  distinguishing  features 
of  this  species  are  the  smooth,  globular  shell,  the  low  spire,  the  broadly 
flattened  columella,  and  the  orange-colored  head  of  the  animal.  It  is 
found  on  Fucus  between  tides,  and  often  associated  with  L.  rudis,  on 
the  whole  coast  north  of  New  Jersey.  The  three  preceding  species 
are  distinctly  boreal  in  their  range,  but  their  place  is  taken  in  south- 
ern Atlantic  waters  of  the  United  States  by  the  following  exceedingly 
common  species: 

L,  irrorata,  A  solid,  robust  shell,  which  attains  a  length  of  about 
one  inch.  It  is  in  many  respects  suggestive  of  L.  litorea,  its  Northern 
relative,  but  the  spire  is  higher,  with  straighter  out- 
lines, and  the  apex  is  acute.  The  surface  is  ornamented 
with  closely  set,  revolving  ribs  5  the  sutures  are  indis- 
tinct ;  the  lip  is  thin,  though  thickened  just  within  5  and 
the  color  is  whitish  to  pale  cinereous  greenish,  sometimes 
spotted  with  broken  brownish  lines.  Within  it  is  white, 
with  a  reddish  tinge  on  the  columella,  and  brownish 
spots  on  the  edge  of  the  lip.  This  species  ranges  from 
Maryland  to  Texas ;  its  station  is  between  tides. 

L,  angiiliferiu  As  the  last  species  resembles  X.  ZiYorm, 
so  this  other  common  Southern  form  resembles  a  greatly  -^^■«<'''''^'*  irrorata. 
developed  and  large  L.  rudis  of  the  smoother  variety. 
It  has  a  high-spired  shell,  with  an  acute  black  tip.  It  has  about  six  whorls, 
which  are  variously  decorated  by  wavy,  oblique  black  lines  and  revolv- 
ing black  lines  broken  into  series  of  dots  and  larger  spots  near  the  suture. 
The  ground-color  varies  from  yellow  to  purple.  None  of  the  colors  are 
very  vivid.  Within  it  is  yellowish- white.  This  species  has  a  much  thinner 
and  more  delicate  shell  than  any  of  the  littorinas  thus  far  considered.  It 
is  common  on  the  piling  of  wharves  and  in  sheltered  nooks  everywhere 


(lASTEROPODS  373 

between  tides.  It  is  essentially  a  tropical  species  of  very  wide  and  ex- 
tended range,  but  it  does  not  occur  north,  of  St.  Augustine.  At  Tampa 
it  has  been  found  in  vast  numbers.     (Plate  LXIX.) 

The  California  coast  furnishes  two  more  species  of  Littorina.  Their 
station  is  among  the  rocks  between  tides,  and  their  habits  are  quite  the 
same  as  those  of  the  east-coast  species. 

L,  scutulata.  In  this  species  the  color  is  of  various  shades,  gener- 
ally dark  gray,  mottled  with  white  spots.  A  good-sized  specimen 
measures  one  half  of  an  inch  in  length.  The  spire  is  high;  the 
columella  flattened,  broad ;  the  shell  is  purplish-white  within  the 
aperture.     (Plate  LXIX.) 

L,  planaxis.  Somewhat  larger  than  the  last ;  wider ;  with  a 
lower  spire ;  grayish  in  color,  sometimes  speckled  with  white ;  chest 
nut-brown  within.  The  columella  is  remarkably  flattened,  and  a 
portion  of  the  whorl  next  bordering  the  columella  is  excavated  as 
though  eaten  away  by  the  animal.  These  two  species  are  often  found 
associated  on  the  rocks.     (Plate  LXIX.) 

Genus  Lacuna 

Closely  allied  to  Littorina  is  the  genus  Lacuna,  one  species  of 
which,  L.  vincta,  is  very  abundant  on  the  New  England  coast. 
A  curious  and  distinguishing  feature  of  this  genus  is  the 
umbilicus,  which  forms  a  lengthened  groove  along  the 
columella.  L.  vincta  rarely  exceeds  one  half  of  an  inch 
in  length,  and  is  thin,  with  a  pointed  spire  of  five  whorls. 
It  is  either  of  a  uniform  horn-color,  or  purplish,  or  banded 
with  chestnut.  It  may  best  be  found  upon  marine  plants 
in  sheltered  places,  or  may  sometimes  be  gathered  in  quantity 
from  the  roots  of  Laminaria  washed  in  by  storms. 

Genus   Tectarius 

The  specific  representatives  of  this  genus  are  mostly  tropical. 
T,  nodulosus  is  abundant  in  Florida.  It  is  about  one  half  of  an 
inch  long,  and  has  the  flattened  columella  and  round  mouth 
characteristic  of  Littorina.  It  is  decorated  somewhat  elaborately 
by  revolving  rows  of  nodules  which  cover  the  entire  shell.  Its 
station  and  habits  are  the  same  as  those  of  Littorinao 

Family  CERiTHiiD.a: 

In  this  family  we  meet  with  a  somewhat  new  type  of  sheU— 
the  long,  turriculate  shell,  with  many  whoais  and  with  a  channeled 


374  MARINE  INVERTEBRATES 

aperture.  The  Cerithiidce  include  a  large  number  of  genera, 
mostly  tropical  in  distribution.  Their  shells  are  usually  highly 
ornamented  in  various  schemes  of  sculpture^  but  they  lack  beauty 
in  color.  The  animal  is  pro^dded  with  a  siphon,  as  is  indicated 
by  the  anterior  canal  of  the  shell.  The  operculum  is  corneous, 
with  a  nearly  central  nucleus. 

Genus   Cerithium 

C,  floridanum,  A  very  common  species  on  the  west  coast  of  Florida, 
also  sparingly  found  at  Hatteras.  It  has  eight  or  ten  whorls,  a  grad- 
ually tapering  spire,  and  a  sharp  apex ;  the  aperture  is  oblong,  with  a 
deeply  cut  anterior  canal  projected  to  the  left  and  backward  (when  the 
specimen  is  held  apex  up,  with  the  aperture  toward  the  observer).  The 
sculpture  is  elaborate,  consisting  of  many  rows  of  revolving  ribs,  and 
close  to  the  suture  there  are  circling  rows  of  nodes.  There  is  a  curious 
hump  just  to  the  left  of  the  aperture,  which  is  quite  characteristic  of  the 
genus.  The  color  is  whitish-gray ;  the  length  one  and  a  quarter  to  one 
and  a  half  inches.  Station,  shallow  water  in  lagoons  and  sheltered 
spots.     (Plate  LXIX.) 

C  muscarum.  Another  Floridian  species,  somewhat  smaller  than 
the  last  (one  inch  in  length).  It  has  heavy,  prominent,  transverse  ribs 
crossed  by  circling  rows  of  chestnut  spots,  one  heavy  revolving  rib 
around  the  base ;  eight  or  nine  whorls ;  a  high-tapering  spire ;  and  a 
sharp  apex.  The  aperture  is  oblong,  with  the  anterior  canal  projecting 
to  the  left.  The  columella  is  arched;  the  color  shining  gray  to  very 
hght  purplish.  This  very  pretty  little  shell  may  be  gathered  literally  by 
the  shovelful  all  along  the  west  Florida  coast  in  sheltered  spots,  on  sandy 
and  shallow  bottoms.     (Plate  LXIX.) 

C  minimum.  A  still  smaller  Floridian  shell,  with  jet-black  aperture 
and  anterior  canal  projecting  horizontally  to  the  left.  The  sculpture- 
plan  is  of  revolving  ribs  and  a  series  of  white  granules  just  below  the 
sutures.  Its.  station  is  the  same  as  that  of  the  last.  Often  the  bottom 
of  a  lagoon  will  seem  to  be  literally  paved  with  these  somber-hued 
little  shells.  From  Tampa  Bay  to  Charlotte  Harbor  they  are  very 
abundant. 

Genera  Bittiufn^  Triforis 

These  are  allied  genera,  having  numerous  species  upon  our 
coasts,  but  the  shells  are  so  small  that  the  inexpert  collector  is 
not  likely  to  notice  them.  Hosts  of  these  minute,  turreted,  de- 
cussated, blackish  shells  are  to  be  found  on  the  wiry  grasses  of 
salt-marshes.  They  are  also  found  on  algse  at  low-water  mark. 
In  Triforis  the  whorls  turn  to  the  left.  Range  from  Cape  Cod  to 
South  Carolina. 


GASTEROPODS 


375 


Genus  Cerithidea 

C.  scalariforniis.  This  species  has  the  suggestive  outHnes  of  the 
family,  but  the  aperture  is  simpler.  The  outer  lip  is  considerably  thick- 
ened, sinuous,  and  yellow ;  there  is  a  very  slight  notch  at  the  angle 
of  the  columella,  and  the  lip  serves  for  an  anterior  canal.  The  apex  is 
wanting  by  reason  of  the  usual  truncation  of  two  or  three  whorls  of  the 
spire.  There  are  revolving  ribs  on  the  base ;  longitudinal  ribs  elsewhere. 
The  color  is  a  dingy  drab ;  within,  brownish-yellow.  It  is  found  in 
brackish  water  in  Georgia  and  Florida.  This  species  is  said  to  suspend 
itself  from  overhanging  vegetation  by  means  of  glutinous  filaments.  It 
may  remain  out  of  water  for  an  almost  indefinite  time.     (Plate  LXIX.) 

C,  sacrata,  A  species  very  common  on  the  mud-flats  of  San  Fran- 
cisco Bay.  It  is  a  high-spired  shell  of  ten  heavily  ribbed  whorls,  with  a 
series  of  revolving  ribs  on  the  body-whorl.  The  outer  lip  is  sinuous, 
and  the  columella  is  slightly  twisted.  It  is  nacreous  and  brown  within, 
dingy  blue-black  without.  Length  one  inch  to  an  inch  and  a  quarter. 
(Plate  LXIX.) 


Family  VEEMETn).E 


Genus  Vermiciilaria 

V,  spirata.  This  is  a  very  curious  creature 
when  considered  from  the  point  of  view  of  the 
gasteropod  moUusk.  It  seems  at  first  as  though 
it  would  be  better  to  regard  it  as  a  worm  which 
had  created  for  itself  a  calcareous  covering.  But 
it  is  a  true  prosobranch  notwithstanding  the  fact 
that  it  has  departed  widely  from  the  conven- 
tional design  in  the  fashioning  of  its  shell.  At 
first  the  shell  starts  out  in  a  regular  form,  and 
then  the  whorls  become  separated,  finally  wander- 
ing about  in  a  seemingly  aimless  manner.  The 
irregular  prolongation  sometimes  measures  ten 
inches  in  length.  The  animal  is  in  no  way  re- 
markable except  in  having  the  viscera  greatly 
elongated  and  the  foot  very  short  and  broad.  The 
color  of  the  animal  is  light  brown  with  black 
spots;  the  shell-color  is  rufous  or  ashy-white. 
Shells  of  this  genus  are  often  found  grouped 
together  in  an  inextricable  mass.  It  is  found 
in  shallow  water  from  New  England  to  Florida. 


Vermicularia  spirata. 


Family  strombid^ 

This  is  a  particularly  interesting  family,  but  it  is  tropical,  and 
is  represented  on  the  shores  of  the  United  States  by  only  one 


376  MARINE  INVERTEBRATES 

genus,  Sh'omhus,  of  which  we  have  but  a  few  species.  Stromhus  is 
a  scavenger,— a  buzzard  among  moUusks,— and  its  sense  of  smell 
is  evidently  very  acute.  Its  eyes  are  much  more  highly  devel- 
oped than  the  usual  gasteropod  visual  organs,  and  they  are  placed 
at  the  tip-ends  of  two  very  substantial  eye-stalks  or  -pedicels. 
The  tentacles  are  slender  and  project  from  the  eye-pedicels.  The 
foot  is  curiously  developed ;  that  portion  of  it  which  would  nat- 
urally constitute  the  creeping-disk  is  exceedingly  small,  but  the 
metapodium  (the  hinder  part  of  the  foot,  upon  which  the  opercu- 
lum is  situated)  is  very  large.  The  corneous  operculum  upon  its 
end,  which  is  far  too  small  to  close  the  entrance  of  the  shell  when 
the  creature  retires  within  it,  looks  like  a  claw.  Instead  of  creep- 
ing along  the  sand,  Stromhus  proceeds  by  jumps  or  awkward 
leaps,  turning  its  heavy  shell  first  to  one  side,  then  to  the  other. 
The  shell  is  usually  heavy,  with  the  outer  lip  greatly  thickened. 

Genus  Stromhus 

S*  pugilis.  The  very  common  Floridian  species,  often  three  to  four 
inches  in  height,  with  a  short  spire  covered  with  nodes  or  short,  ob- 
tuse spines,  which  are  also  found  upon  the  shoulder  of  the  body- whorl 
(sometimes  smooth).  The  aperture  is  long,  with  a  wide  notch  in  the 
outer  lip  and  a  posterior  canal.  Living  specimens  have  a  tough,  leathery 
epidermis  covering  at  least  the  body-whorl.  The  color  is  brownish. 
The  columella  is  covered  with  a  fairly  thick  callous  deposit,  and,  as 
within  the  aperture,  is  highly  polished,  and  deep  purple,  blackish-chest- 
nut, or  vivid  carnation-red  in  color.  The  smoother  varieties  have  gone 
under  the  name  of  S,  alatus,  but  the  identity  of  the  two  species  is  as- 
sured. This  pugihstic  Stromhus  is  a  very  active  moUusk,  and  when 
placed  in  a  boat  will  sometimes  effect  its  escape  over  the  side  in  a  most 
surprisiug  manner.  The  species  is  very  abundant  in  aU  the  shallow 
waters  of  Florida.  A  piece  of  meat  on  a  string,  left  overnight  in  some 
sheltered  sandy  spot  where  there  are  from  six  to  eight  feet  of  water, 
will  surely  attract  them.  In  Florida,  where  the  waters  teem  wdth  life, 
unless  the  bait  is  protected  in  a  wire  cage,  the  chances  are  that  the  hosts 
of  crustaceans  and  fish  wiU  make  away  with  it  long  before  the  strombs 
can  arrive  on  the  scene.     (Plate  LXX.) 

S,  gigas.  One  of  the  largest  of  gasteropods,  very  common  on  the 
Florida  Keys  and  also  occurring  in  southern  Florida.  Hundreds  of 
thousands  of  these  shells  have  been  sent  to  Europe  from  the  Bahamas 
to  be  cut  into  cameos.  This  familiar  shell  is  to  be  seen  everywhere  in 
the  Southj  placed  about  flower-gardens  and  lining  the  paths  and  walks 
in  yards.  It  is  generally  known  in  Florida  and  the  West  Indies  as  the 
*'  conch-sheU."  The  animal  is  used  as  food  in  Key  West,  and  is  very 
generally  eaten  throughout  the  Bahamas.    From  their  habit  of  eating 


PLATE   LXIX. 

1,  Littorina  angulifera,  twice  natural  size.  4,  Cerithium  floridanum. 

2,  Littorina  scutulata,  much  enlarged.         5,  Cerithium  muscarum. 

3,  Littorina  planaxis,  enlarged.  6,  Cerithidea  scalariformis,  enlarged. 

7,  Cerithidea  sacrata. 


PLATE  LXX. 

1,  Strombus  pugilis.  3,  Trivia  pediculus. 

2,  Cyprsea  exanthema.  4,  Trivia  calif omica. 

5,  Trivia  quadripunctata. 


GASTEROPODS  377 

these  animals  the  natives  of  some  of  the  Bahama  Islands  are  themselves 
called  ''  Conchs."     The  rich  pink  color  of  the  shell  is  very  striking. 

There  are  perhaps  seventy-five  or  eighty  species  of  Stromhus  inhabit- 
ing the  tropical  seas,  and  many  of  them  are  highly  prized  by  collectors 
on  account  of  their  great  beauty. 


Family  cype^id^ 

Genus  Cyprcea 

Cyprcea  is  one  of  the  ''  aristocratic"  genera.  Whether  the  shell 
or  the  animal  itself  is  considered,  there  is  probably  no  genus  of 
mollusks  which  offers  so  much  of  beauty  and  interest  to  the  col- 
lector and  student.  The  genus  is  a  tropical  one,  and  finds  its 
metropolis  among  the  coral-fringed  islands  of  the  equatorial 
Pacific.  Despite  their  brilliant  colors  and  general  attractiveness, 
the  cowries— for  such  is  their  popular  name— are  very  modest  and 
shy ;  they  prefer  to  hide  among  rocks,  where  they  may  be  secure 
from  molestation,  for  probably  their  conspicuous  appearance  is  a 
real  source  of  danger  to  them.  In  the  animal  of  Cyprcea  the  mantle 
is  provided  with  two  large  lateral  lobes,  which  are  reflexed  and 
meet  over  the  top  of  the  shell;  thus,  when  the  mantle  is  fully 
extended,  the  shell  is  entirely  concealed.  These  mantle  lobes  are 
often  furnished  with,  numerous  forked,  tufted,  or  ramified  fila- 
ments. The  foot  is  long;  there  is  no  operculum.  The  color  of 
the  animal  is  often  very  striking  in  its  intensity.  A  description 
of  the  cowry-shell  is  hardly  necessary,  so  familiar  is  every  one 
with  it.  A  deposit  of  enamel  is  made  all  over  the  shell,  and  its 
painting  and  decoration,  usually  very  elaborate,  is  reserved  for 
the  adult  as  a  final  process  in  the  artistic  completion  of  its  home. 
The  aperture  is  as  long  as  the  shell,  is  channeled  at  both  ends, 
and  is  toothed  along  both  margins.  The  spire  is  insignificant  and 
is  concealed  by  layers  of  enamel.  In  the  young  the  shell  has  a 
very  different  appearance,  resembling  a  sharp-lipped  Oliva,  and 
its  scheme  of  coloration  may  be  entirely  different  from  that  em- 
ployed by  the  adult. 

Among  the  Cyprceidce  are  many  remarkable  species.  The  splen- 
did Cyprcea  aiirantia,  a  native  of  the  Fiji  Islands,  is  one  of  the 
shells  most  sought  after  by  enthusiastic  collectors.     The  natives 


378  MARINE  INVERTEBRATES 

learned  its  value  long  ago,  and  hold  specimens  of  it  at  very  sub- 
stantial prices.  It  is  worn  as  an  ornament  by  chiefs  and  as  a  mark 
of  distinction.  The  well-known  C  moneta,  also  a  native  of  the 
Pacific  Islands,  has  been  very  extensively  used  as  mone^y  through- 
out the  South  Seas  and  in  Africa.  There  are  many  collectors  of 
shells  who  confine  their  efforts  almost  exclusively  to  this  and  to 
one  or  two  of  the  other  ^'  aristocratic  "  genera.  From  an  esthetic 
point  of  view  this  is  very  natural,  but  biologically  the  less 
pretentious  mollusks  are  quite  as  interesting. 

Of  the  one  hundred  and  fifty  or  more  species  in  existence  only 
three  are  to  be  found  upon  the  Atlantic  coast  of  the  United  States, 
and  the  chances  are  decidedly  against  the  finding  of  any  of  them 
north  of  extreme  southern  Florida. 

C,  exanthema,  A  species  not  uncommon  at  Key  West,  where  it  may 
be  seen  slowly  crawhng  about  the  mangrove  roots  near  the  water's 
edge.  It  attains  a  length  of  from  four  to  six  inches,  and  is  so  highly  pol- 
ished that  a  good  specimen  could  be  used  as  a  mirror.-  In  color  it  is 
shining,  hght  chestnut,  clouded  with  purple  ;  the  lips  are  a  dark,  very  rich 
chestnut ;  over  all  are  whitish  spots  which  appear  to  shine  forth  from 
beneath  the  enamel.  Lengthwise  along  the  middle  of  the  back  is  a 
zone  of  lighter  color  which  reflects  a  purplish  sheen.     (Plate  LXX.) 

C.  spurca.  Another  Floridian  species,  properly  belonging  to  the 
West  Indian  fauna.  It  is  not  more  than  one  half  an  inch  long,  and  is 
white  in  color,  but  it  is  so  thickly  dotted  with  yellow  spots  upon  the  back 
that  it  would  pass  for  a  yeUow  shell.  The  base  is  pure  white.  The  sur- 
face of  the  sheU  glistens  in  the  light. 

Genus  Trivia 

In  the  genus  Trivia  the  shell  is  shaped  in  every  way  like  that  of 
Cyprcea,  but  its  surface  is  never  smooth.  In  the  middle  of  the 
back  is  a  longitudinal  groove,  from  which  run  transverse 
ribs,  which  continue  around  to  and  enter  into  the  aperture.  The 
shells  are  always  small,  never  exceeding  one  half  of  an  inch  in 
length,  and  their  color  is  generally  reddish  or  brownish,  passing 
to  pink. 

T,  2^€diculus.  A  Floridian  species,  first  described  by  the  great  natu- 
ralist Linnaeus.  Like  most  of  the  descriptions  of  the  earlier  naturalists, 
this  is  very  short  and  inadequate,  and  would  apply  equally  well  to  al- 
most any  Trivia.  The  color  is  rose-pink,  with  several  large  brownish 
splashes  on  the  back.  The  spire  is  entirely  hidden.  It  is  found  in  shal- 
low water  in  pools,  and  on  the  beach  after  storms.     (Plate  LXX.) 


G^STEROPODS  379 

T.  quadripunctata.  Much  smaller  than  the  preceding;  rose-red, 
with  four  conspicuous  reddish-brown  dots  on  the  back,  two  on  each 
side  of  the  median  dorsal  groove.     Found  in  Florida.     (Plate  LXX.) 

On  the  California  coast  are  also  several  species  of  Trivia  and  one 
Cyprcsa,  but  they  belong  to  the  Southern  California  peninsula,  and  are 
not  commonly  found  farther  north  than  Santa  Barbara.  The  cowry  is 
called  C.  spadacea  ;  it  grows  to  a  length  of  about  two  inches,  is  highly 
polished,  with  white  base  and  sides,  and  is  bright  chestnut  above.  As 
is  usual  in  the  cypraeas,  the  spire  is  covered  with  enamel. 

T,  califomica.  A  species  found  at  Monterey  and  thence  south.  It 
lacks  the  median  dorsal  groove,  and  has  a  whitish  color-streak  instead. 
The  ribs  are  white,  and  the  ground-color  of  the  shell  is  dark  brownish- 
red.  These  little  shells,  when  found  upon  the  beach,  are  called  ^'coffee- 
shells,"  from  their  somewhat  striking  resemblance  to  the  coffee-bean, 
being  flat  on  one  side  and  rounded  upon  the  other,  and  otherwise  resem- 
bhng  it  in  size  and  color.     (Plate  LXX.) 

T.  solandri.  This  species  may  be  found  at  Santa  Barbara  and  San 
Diego.  It  is  twice  as  large  as  the  last  species,  and  has  a  very  deep  groove 
in  the  back  and  widely  separated  ribs.  Color  rose  to  brown.  The 
groove  on  the  back  penetrates  into  the  white  portion  of  the  shell. 

Family  doliidje 

This  small  family  furnishes  two  conspicuously  handsome  spe- 
cies belonging  to  the  genus  Bolium,  which  range  from  Hatteras 
southward  into  the  West  Indies. 

Genus  Doliufu 

D,  galea  and  X).  jyerdix.  The  animal  in  both  of  these  species  has  a  rela- 
tively large  foot,  which  spreads  out  while  in  the  act  of  creeping  and  seems 
far  too  bulky  ever  to  be  withdrawn  into  the  shell.  It  is  square  in  front, 
and,  bulging  out  far  to  each  side,  tapers  to  a  blunt  point  behind.  The 
most  noticeable  feature  of  the  animal,  however,  is  the  great  develop- 
ment of  its  proboscis,  which  is  quite  as  long  as  the  shell  itself.  The 
siphon  is  also  long  and  is  curved  over  the  back  of  the  shell.  The 
operculum  is  wanting  in  adult  specimens.  The  shell  of  D.  galea  some- 
times attains  a  length  of  eight  inches,  with  a  diameter  of  about  six  inches ; 
the  other  species  is  not  quite  so  large.  They  are  both  ventricose, 
thin,  inflated  shells,  with  large  body- whorls  and  crenulated  Hps.  Both 
are  slightly  umbilicated  and  ornamented  with  revolving,  regularly  spaced 
ribs.  The  ribs  of  B.  perdix  are  not  so  highly  raised,  but  they  are  painted 
with  light  reddish-brown  spots.  B.  galea  is  white,  with  a  lower  spire  and 
deenly  channeled  sutures.     (Plate  LXXI.) 

Genus  Pyriila 

P.  papyratia.  One  of  the  commonest  as  well  as  one  of  the  hand- 
somest of  American  shells.  It  is  a  Floridian  species,  found  in  shal- 
low water  and  on  sandy  bottoms.     The  animal  greatly  resembles  that 


380  MARINE  INVERTEBRATES 

of  Dolium,  except  that  it  has  two  side-flaps,  which,  when  extended, 
partially  inclose  the  shell.  The  shell  is  thin,  with  an  almost  flat  spire 
and  a  greatly  enlarged  body-whorl.  The  aperture  is  flaring,  and  is 
drawn  out  anteriorly  into  a  tapering  canal,  which  gives  to  the  shell  the 
outlines  of  a  pear.  The  ornamentation  is  revolving,  but  not  highly 
raised,  and  there  are  ribs  with  very  distinct  longitudinal  lines  of  gTowth 
between.  The  color  is  pure  white,  or  sometimes  yellowish,  with  rufous 
spots ;  within  it  is  golden.  This  attractive  shell  is  usually  from  three 
to  four  inches  in  length,  but  is  sometimes  found  considerably  larger^ 
(Plate  LXXI.) 

Family  cassidid^ 
Genus    Cassis 

The  cassides,  commonly  known  as  the  "  helmet-shells,"  are  car- 
nivorous mollusks^  which  lead  an  active  life  in  sandy  stations, 
prowling  about  in  search  of  bivalves,  upon  which  they  prey. 
They  have  a  large  siphon  and  a  fairly  large  and  extensible  pro- 
boscis. The  foot  is  broad  and  strong,  being  well  adapted  for  plow- 
ing through  the  sand.  The  shell  of  Cassis  is  large,  generally 
heavy  and  inflated,  with  a  short  spire  and  a  short,  recurved  ante- 
rior canal.  The  lip  is  much  thickened.  Upon  the  Atlantic  coast 
of  North  America  there  are  four  species  of  Cassis.  They  are  aU 
properly  West  Indian  in  their  faunal  relations,  but  have  found 
lodgment  on  the  American  shore  at  various  points.  All  of  them 
have  been  taken  in  the  neighborhood  of  Cape  Hatteras,  two  of 
them  in  "West  Florida,  and  two  in  Texas. 

C,  tuberosa,  A  large,  heavy  sheU,  often  from  six  to  eight  inches  in 
length,  with  a  flattened  spire.  The  aperture  is  long  and  narrow,  with 
large  white  teeth  upon  the  outer  lip,  which  is  also  greatly  thickened. 
The  columellar  lip  is  ribbed.  A  heavy  deposit  of  enamel  to  the  left  of 
the  columellar  lip  gives  the  shell  a  triangular  outline.  A  row  of  very 
large  nodes  upon  the  shoulder  of  the  body-whorl  and  two  rows  of  obso- 
lete nodes  below  are  characteristic  features  of  this  species.  The  color  is 
light  yellowish -brown  suffused  with  pink.  The  aperture  and  the  columel- 
lar callosity  are  flesh-tinted,  with  chestnut  trimmings.  The  anterior  canal 
is  deep  and  recurved. 

C.  cameo.  A  species  of  about  the  same  size  as  the  last,  but  more 
ovate  or  ventricose  in  form.  It  is  coarsely  striated,  with  elevated  growth- 
lines,  and  has  circling  rows  of  large,  rib-hke  elevations,  having  some- 
times nodes  upon  the  body-whorl.  The  columella  is  conspicuously 
ribbed  and  greatly  expanded.  The  outer  lip  is  thickened,  and  has 
lamelliform  teeth  within.  Flesh-colored^  teeth  white ;  purple-brown 
trimmings.    A  great  many  of  these  shells  are  sent  yearly  from  Nassau 


GASTEROPODS  381 

to  Italy,  where  they  are  used  in  cameo-cutting.  It  is  owing"  to  the  fact 
that  the  substance  of  these  shells  is  deposited  in  layers  of  different  colors 
that  they  are  available  for  this  purpose.  There  are  about  fifty  species 
of  helmet-shells,  the  one  most  valued  for  cameo-cutting  being  known 
as  the  black  helmet,  C.  Madagascarensis. 

C,  testiciihis.  A  species  found  outside  of  the  West  Indies  only  at 
Key  West  and  at  Hatteras,  where  the  Gulf  Stream  has  brought  so  raany 
West  Indian  forms,  and  left  them  at  the  point  where  it  takes  its  oblique 
course  away  from  the  shore.  This  pretty  species  is  smaller  than  the 
others  just  described.  It  has  a  low,  depressed  spire ;  longitudinal  ribs 
crossing  wide,  flat  revolving  ribs;  a  long,  narrow  aperture;  and  a 
reflexed  and  thickened  outer  lip,  also  toothed.  The  columella  is  thick- 
ened and  ribbed.  The  anterior  canal  is  recurved  over  the  back  of  the 
shell,  as  is  usual  in  the  genus.  The  color  is  bluish,  with  dark  spots. 
There  are  square  black  spots  on  the  reflexed  lip ;  the  aperture  is  pink, 
and  the  teeth  and  columellar  ribs  white.  This  species  is  exceedingly 
common  at  Nassau,  and  plays  havoc  with  the  more  slowly  moving 
bivalves,  which  it  devours.     (Plate  LXXI.) 

C.  inflata.  Perhaps  the  commonest  species  of  Cassis  on  our  coast. 
It  is  reported  to  be  common  at  Beaufort,  South  Carolina,  yet  it  is  not  so 
frequently  met  with  out  of  the  West  Indies  as  some  earlier  collectors 
would  have  us  beheve.  Beach-worn  specimens,  however,  are  not 
unusual  all  along  the  Florida  coast.  It  attains  a  size  of  from  three  to 
four  inches,  and  is  a  rounded,  globose,  ventricose  shell,  with  a  higher  spire 
than  is  usual  in  this  genus.  The  surface  is  almost  smooth,  the  series  of 
revolving  ribs  being  scarcely  raised  on  the  body-whorl.  The  lip  is 
thickened  and  reflexed,  with  prominent  lamellif  orm  teeth  which  continue 
as  internal  ribs.  The  lower  portion  of  the  columella  is  calloused  and 
roughly  granulated.  The  color  is  bluish-white,  glazed,  with  large  square 
brown  spots.  The  region  of  the  aperture  is  pure  white.  The  collector 
should  not  remain  content  with  a  specimen  or  two  of  the  poor  beach-worn 
shells  of  this  species.  In  general,  this  advice  applies  to  the  collection  of 
all  specimens.  One  can  get  no  idea  of  the  sculpturing  and  painting  of 
shells  from  dead  and  worn  specimens.  It  is  quality  rather  than  quantity 
that  makes  an  interesting  cabinet.     (Plate  LXXI.) 

Family  MURiciDiE 
Subfamily  mueicin^ 

It  seems  like  making  a  long  leap  to  pass  suddenly  from  the 
Cassididce  to  the  Muricidce.  In  the  natural  biological  order,  as  it 
appears  in  our  present  state  of  knowledge,  a  host  of  families  and 
genera  intervene  between  these  two.  But  they  are  omitted  here, 
either  because  they  do  not  conspicuously  occur  upon  our  own 
shores,  or  because  they  are  free-swimming  pelagic  mollusks, 
which  live  only  far  out  at  sea  and  rarely  are  found  on  the  beaches. 
The  family  Muricidce  is  an  exceedingly  large  one,  including  a  be- 


382  MARINE  INVERTEBRATES 

wildering  number  of  well-characterized  genera.  It  has  many 
representatives  in  every  sea,  but,  as  is  apt  to  be  the  case,  the 
finest  and  most  striking"  species  are  tropical.  The  animal  is  not 
peculiar  in  any  way,  being  altogether  a  couventional  prosobranch 
gasteropod,  with  moderately  long  foot,  and  the  usual  tentacles 
placed  upon  a  small  head.  There  is  a  retractile  proboscis,  which 
suggests  carnivorous  habits.  In  reality  the  Mtiricidce  are  per- 
fect pirates  among  the  Molhisea,  attacking  nearly  every  species 
they  encounter,  piercing  its  shell  and  devouring  the  unfortunate 
inhabitant.  They  live  in  rocky  and  gravelly  places  or  about 
coral  reefs.  Their  shells  are  seldom  colored, except  about  the  aper- 
ture. What  the  shells  lack  in  color,  however,  they  fully  gain  in 
oddness  of  form  and  in  sculpturing.  The  anterior  canal  varies 
from  a  mere  notch  to  an  astonishingly  long  channel.  The  ten- 
dency to  nodes,  varices,  spires,  and  varicose  processes  in  general 
is  a  prominent  feature  of  the  family. 

There  are  several  genera,  with  numerous  species,  upon  the  east 
and  west  coasts  of  the  United  States,  but  we  can  do  no  more  here 
than  mention  those  which  are  very  common. 

Genus  Murex 

Of  this  tropical  genus  there  are  two  Floridian  species— il[f. 
rufus  and  M.  pomum.  The  genus  has  been  very  extensively 
divided  into  subgenera,  based  upon  shell-characters  alone.  Some 
of  these  subgenera  are  usually  accepted  at  full  generic  value,  and 
their  substitution  for  the  old,  well-established  name  Murex  is  to 
be  expected.  These  two  Floridian  species  fall  within  different 
subgeneric  lines,  and  the  student  who  goes  to  a  museum  to  com- 
pare his  catch  with  the  labeled  specimens  on  exhibition  will 
probably  be  puzzled  to  find  his  two  murices  named  CMcoreiis 
rufus  and  Phyllonotus  pomum  respectively.  But  for  our  purposes 
the  name  Murex  will  do  well  enough. 

M,  rufus.  This  species  scarcely  ever  exceeds  three  inches  in  length. 
Its  spire  is  moderately  high,  and  the  aperture  is  oblong-ovate,  with  a 
long,  slightly  curved,  and  almost  completely  inclosed  anterior  canal. 
Through  the  end  of  this  the  fleshy  siphon  projects  in  life.  The  shell  is 
most  extravagantly  sculptured  —  so  intricately  that  it  is  difficult  to 
describe  it.    Its  most  conspicuous  feature  is  the  large  f oliaceous  varices 


Doliura  galea. 
Cassis  testiculus. 


PLATE   LXXI. 
Pyrula  papyratia. 


Dolium  perdix. 
Cassis  inflata. 


Murex  rufus. 
Pteronotus  festivus. 


PLATE   LXXII. 

Murex  pomum. 
Cerostoma  foliatum. 


Ocinebra  poulsoni,  enlarged- 
Cerostoma  nuttallii. 


GASTEROPODS  383 

which  cross  the  whorls,  projecting  almost  one  fourth  of  an  inch  from  the 
body  of  the  shell.  Between  each  of  these  varices  is  a  large  node.  There 
is,  besides  all  this,  a  system  of  pronounced  revolving  ribs  which  cross 
the  varices  and  nodes,  giving  to  the  shell  a  greatly  roughened  appear- 
ance. The  interior  is  bluish- white.  The  operculum  is  corneous,  with  a 
subterminal  nucleus.  Unfortunately,  this  really  handsome  shell  is  usually 
incrusted  with  coralline  or  calcareous  matter,  which  must  be  removed 
with  acid  before  a  good  idea  of  its  appearance  can  be  had.  In  color  it  is 
reddish-brown  to  dark  chestnut  on  the  varices.  It  is  very  common  on 
the  west  coast  of  Florida,  but  rarer  elsewhere.     (Plate  LXXII.) 

M,  poimmi,  A  more  abundant  species,  found  all  along  the  coast 
from  Hatteras  to  Texas.  It  is  not  so  elongated  as  the  last,  and  its  sculp- 
tural design  is  much  less  exaggerated.  Between  each  of  the  varices  are 
two  nodules.  The  aperture  is  oblong-ovate,  and  the  anterior  canal  is 
nearly  closed  and  recurved  toward  the  back.  Revolving  ribs  cross  the 
varices  and  nodules.  The  color  is  ashen,  with  chestnut  tips  upon  the 
nodes  and  varices,  and* chestnut-colored  patches  about  the  aperture.  The 
varices  are  simple  and  not  foliaceous  as  in  M.  rufus  ;  the  shell  is  more 
globose.     Length  two  to  three  inches.     (Plate  LXXII.) 

M,  (Phyllonotus)  fiilvescens.  The  largest  of  the  American  murices. 
It  is  not  commonly  found  except  in  Texas. 

Genus   Trophon 

T,  clathratus,  A  fairly  common  shell  of  the  Maine  coast ; 
although  it  belongs  to  a  deeper  zone  than  that  of  the  tides,  it  is 
occasionally  found  after  storms  upon  the  shore.  It  is  a  small 
fusiform  shell,  with  many  prominent  longitudinal  ribs  and  a 
produced  anterior  canal.  Trophon  is  a  boreal  genus,  which  finds 
the  best  conditions  for  life  in  the  icy  waters  of  Labrador  and 
Greenland. 

Genus  Tlrosalpinoc 

The  genus  Urosalpinx  is  closely  allied  to  Murex  and  Trophon. 
Several  of  its  species  are  found  on  the  east  coast  of  the  United 

States. 

U,  cinerea.  This  well-known  species  is  regarded  by 
Chesapeake  and  Long  Island  Sound  oystermen  much  in  the 
light  of  a  plague.  These  active  predaceous  moUusks  live 
upon  bivalves,  and  preferably  upon  oysters.  They  bore  a 
small  round  hole  through  the  shell  of  their  helpless  victims, 
and  then  proceed  to  extract  the  succulent,  fleshy  animal 
from  within.  The  oystermen  call  them  by  the  suggestive 
name  of  '^  drill,"  and  wage  incessant  warfare  upon  them. 
In  some  years  these  mollusks  appear  to  go  into  partnership 
with  the  large  starfish,  Asterias,  and  the  combination  of  the 
Urosalpinx  ^^^  ^^^  soou  dcstroy  any  oyster-bed.  The  original  home  of 
cinerea.         this  destructive  little  creature  is  presumed  to  be  in  Chesa- 


384  MARINE  INVERTEBRATES 

peake  Bay,  but  the  transplanting  of  oyster-spat  thence  to  Long  Island 
Sound  has  introduced  the  enemy  at  the  same  time.  The  species  has  a 
wide  range  from  Florida  to  Cape  Cod,  and  locally  north  of  that  point; 
in  fact,  it  may  be  counted  upon  to  appear  wherever  there  are  oyster- 
beds.  The  shell  is  dingy  gray  in  color,  and  its  whorls  are  crossed  by 
a  dozen  or  more  rib-like  undulations,  and  numerous  revolving  striae. 
The  anterior  canal  is  produced,  and  is  yellowish-brown  within.  Length 
under  an  inch. 

GrENus  Eupleura 

E,  caudata,  A  curiously  flattened  shell  which  has  close 
family  connections  with  that  last  described.  The  peculiarly  flat 
appearance  is  due  to  the  fact  that  there  is  a  rather  wide  varix 
upon  each  side  of  the  shell.  It  is  a  small  species,  never  more 
than  an  inch  in  length,  dingy  gray,  with  longitudinal  undula- 
tions upon  the  whorls,  and  a  long,  narrow  anterior  canal  and 
crenulated  lip.     The  animal  is  white  and  yellow,  and  is  nota- 

Eupieura     ble  for  its  activity.     Found  from  Maine  to  Florida,  about  low- 

caudata.      tide  mark. 

Oa  the  west  coast  of  the  United  States  occurs  a  striking  devel- 
opment of  a  group  of  the  MuricidcB  of  a  curious  foliaceous  ap- 
pearance, belonging  to  the  genera  Fteronotus,  Ocinehra,  and 
Cerostoma. 

Genus  Pteronotus 

P,  festivus.  The  shell  is  marked  by  three  well-raised  varices  upon 
each  whorl,  which  are  reflexed  backward ;  between  each  varix  is  a 
rounded  knob.  All  is  covered  with  numerous  spiral  lines  of  sculpture, 
which  upon  crossing  the  varices  are  frilled.  The  aperture  is  oval  and 
white  within ;  the  anterior  canal  is  entirely  closed  and  is  reflexed  slightly 
over  the  back.  Length  two  inches ;  color  dingy  white.  Found  on  the 
southern  coast  of  California.     (Plate  LXXII.) 

Genus  Ocinehra 

O.  poulsoni.  This  has  the  same  dingy  white  color  as  the  species  last 
described.  Its  plan  of  sculpturing  is  somewhat  different  and  consists  of 
a  series  of  rounded  varices,  about  nine  to  a  whorl,  crossed  by  spiral  lines. 
The  anterior  canal  is  open,  and  just  within  the  white  aperture,  upon  the 
inner  side  of  the  lip,  is  a  series  of  five  or  six  little  round  teeth.  This  species 
frequents  the  waters  near  San  Diego,  and  sometimes  grows  to  be  two 
inches  in  length.     (Plate  LXXII.) 

O.  lurida,  A  much  smaller  species  than  the  last,  being  not  more  than 
one  half  to  three  fourths  of  an  inch  in  length.  Very  common  at  Mon- 
terey and  in  San  Francisco  Bay.  It  is  strongly  marked  with  spiral  lines 
covering  the  longitudinal  undulations  usually  found  in  this  genus,  but 
which  are  less  prominently  developed  in  this  case. 

There  are  several  species  of  small  ocinebras  upon  the  California  coast, 
but  they  are  not  easily  determined  without  a  more  critical  examination 


GASTEROPODS  385 

than  we  are  giving  our  specimens.  They  are  O.  interfossct^  a  small  shell 
with  deep  spiral  grooves,  sharp  varices,  and  deep  sutures ;  and  O.  eir- 
cumtexta,  also  small,  but  heavy,  short- spired,  with  scalloped  or  crenu- 
lated  outer  lip. 

Genus  Cerosfoiua 

C  nuUallii,  A  species  belonging  to  the  southern  coast  of  California. 
It  may  be  recognized  at  once  by  two  prominent  characters  :  first,  a  horn- 
like projection  from  near  the  base  of  the  outer  Up,  and,  second,  the  tumid 
varices  alternating  with  rounded  knobs.  It  has  no  spiral  series  of  lines 
hke  those  in  Pteronotus  festivus  ;  and  it  has  a  row  of  five  or  six  httle  teeth 
upon  the  inner  side  of  the  aperture,  like  those  in  Ocinebra  poulsoni.  The 
anterior  canal  is  closed.     It  is  about  two  inches  long.    (Plate  LXXII.) 

C.  foliatum,  A  shell  somewhat  like  the  last,  but  almost  twice  as 
large,  with  heavy  wing-hke  varices  (three  upon  each  whorl),  made  up 
of  overlapping  plaits.  The  knobs  between  the  varices  are  much  smaller, 
whUe  the  revolving  ribs,  though  fewer  in  number  than  in  most  of  these 
west-coast  murices,  are  heavy  and  large.  The  aperture  is  oblong,  the 
anterior  canal  closed.  There  is  a  "horn  "  near  the  base  of  the  aperture, 
as  in  C.  mittallii,  but  no  row  of  teeth  upon  the  under  side  of  the  lip. 
The  color  is  dingy  white.     (Plate  LXXII.) 

In  the  waters  of  Oregon  and  Washington  there  are  a  few  trophons  and 
other  forms  similar  to  the  east-coast  genera.  These  no  doubt  belong  to 
the  boreal  and  arctic  faunal  provinces,  and  have  spread  over  both  the 
Atlantic  and  Pacific  northern  regions. 

Subfamily  puepurin^ 

This  is  considered  a  subfamily  of  the  Mmicidce,  and  the  gronp 
therefore  bears  the  subfamily  termination  -ince.  There  is  no 
vital  difference  between  it  and  the  subfamily  Muricince.  The 
operculum  in  the  Piirpurince  has  a  lateral  nucleus  instead  of  a 
subterminal  one,  but  beyond  this  there  are  no  essential  differ- 
ences. The  shell  of  the  purpuras  is  generally  heavy  and  solid, 
being  adapted  to  a  life  among  rocks  which  are  exposed  to  the 
beating  of  the  surf.  There  is  a  lack  of  that  extravagant 
sculptural  design  so  characteristic  of  the  true  murices,  most  of 
the  purpuras  being  comparatively  smooth,  in  order,  no  doubt, 
that  they  may  offer  as  little  resistance  as  possible  to  the  rushing, 
seething  waters  of  exposed  rocky  shores. 

The  Furpurince,  like  some  of  the  murices,  when  mutilated, 
exude  a  reddish-purple  fluid.  On  account  of  this,  the  ancient 
Romans  used  to  gather  great  quantities  of  certain  Mediterranean 
forms  belonging  to  these  families,  place  them  in  large  mortars, 

25 


386  MARINE  INVERTEBRATES 

and  grind  them  up,  shell  and  all.  A  garment  dipped  in  tlie 
mixture  and  then  exposed  to  the  sun  would  receive  a  rich  purple 
dye.  This  was  the  basis  of  the  famous  "  Tyrian  purple."  The 
process  was  lost,  and  was  rediscovered  many  centuries  later,  but 
it  was  long  ago  abandoned  in  favor  of  the  far  superior  modern 
chemical  dyes. 

Genus  I^urpura 

P,  lapilhis.  No  one  who  has  ever  spent  an  observant  hour  among  the 
rocks  at  low  tide,  on  the  shores  of  Massachusetts  or  Maine,  has  failed  to 
notice  the  myriads  of  P.  lapillus  clinging  to  the  barnacle-covered  boul- 
ders, or  slowly  creeping  about  in  the  tide-pools.     This  rather  pretty  little 

mollusk  is  a  native  of  Great  Britain,  and  there 
attains  its  greatest  development  and  exhibits 
best  its  marvelous  range  of  variation.  It  is 
presumed  to  be  an  immigrant  in  American 
waters,  having  found  its  way  across  the  sea 
by  Iceland  and  Greenland,  and  thence  down 
the  coast.  As  it  is  a  cold-water  animal,  and 
can  only  survive  in  open,  rocky  stations,  it  will 
probably  never  pass  south  of  New  York.  It  is 
youn  Tr'^s  'eci^  difficult  to  dcscribc  this  well-known  species 
Purjynra  lapillus.      ^^^Sen!^^"^^    bocause  it  is  SO  extremely  variable.     There  is 

an  individuality  about  the  species  which  causes 
it  to  be  recognized  at  once,  yet  its  details  are  elusive.  It  is  never  more 
than  one  and  a  half  inches  long  (in  the  United  States),  and  varies  in  color 
from  white  through  yellow  to  chocolate.  Often  it  is  banded  in  yellow 
or  brown.  Near  the  only  sand-beach  of  Bar  Harbor  is  a  colony  with  ver- 
milion bands.  The  shell  varies  from  a  smooth  to  an  exceedingly  rough 
exterior,  the  latter  being  caused  by  raised  scales  along  the  lines  of  growth, 
which  make  the  shell  even  prickly  to  the  touch.  Of  this  latter  form  there 
is  a  large  colony  on  Campobello  Island.  Numerous  coarse  revolving 
ridges  are  common.  The  columella  is  flattened  and  smooth,  and  its  lower 
portion  is  a  little  twisted.  The  anterior  canal  is  short.  P.  lapillus  has 
been  accused  of  attacking  clams  and  boring  their  shells,  as  does  the  pre- 
daceous  Urosalpinx  cinerea,  but  the  accusation  is  not  well  founded.  Pur- 
pura is  carnivorous,  and  no  doubt  destroys  many  young  barnacles ;  but 
with  its  short  and  small  foot  it  would  find  great  difficulty  in  digging 
in  the  sand  for  clams. 

In  Florida  waters  there  are  several  purpuras,  which  properly  belong  to 
the  West  Indian  fauna,  but  enjoy  an  extensive  range. 

I*,  patula.  This  species  has  a  rounded  body- whorl,  and  sometimes 
a  low  spire,  which  give  it  much  the  appearance  of  a  large  limpet.  Its 
back  is  decorated  with  rows  of  nodules  in  regular  order,  forming  a 
spiral  series.  The  chief  point  of  distinction  is  the  deeply  excavated, 
broadened,  and  flattened  columella-lip  of  salmon-color.  A  portion  of 
the  whorl  itself  is  worn  down  and  made  smooth  by  being  dragged  oyer 
sharp  coral  rocks,  revealing  underneath  the  rough,  incrusted  exterior, 
a  transparent  colorless  shelly  substance.      Dark  and  chestnut-colored 


GASTEROPODS  387 

patcnes  and  spots  adorn  tlie  outer  lip.      The  shell  is  from  two  to  two 
and  a  half  inches  long.     (Plate  LXXIII.) 

P.  Jicemastoma,  Like  its  relative,  P.  lapillus  of  Northern  waters, 
this  species  is  so  variable  as  almost  to  defy  description.  The  form 
that  usually  occurs  from  Hatteras  to  Florida  is  of  a  bluish-gray  color, 
and  is  indistinctly  encircled  with  narrow  yellow  zones,  which  are  crossed 
by  somewhat  vague  longitudinal  waves  of  black.  The  columella  and 
outer  lip  and  interior  are  orange-yellow.  The  spire  is  moderately  high, 
with  a  sharp  apex.  The  whorls  are  noduled  upon  the  shoulder.  There 
are  revolving  grooves  throughout,  even  within  the  aperture.  A  Texan 
variety  of  this  species  has  a  much  more  elevated  spire,  with  channeled 
sutures,  and  small   aperture  of  bright  salmon-color. 

Upon  the  Californian  coast  there  are  three  species  of  Purpura,  which 
markedly  resemble  the  P.  lapillus  of  the  Maine  shores.  Their  extreme 
variability  has  given  rise  to  much  confusion  in  their  nomenclature; 
the  multitude  of  names  given  by  numerous  authors  to  the  varietal  forms 
of  these  three  species  constitute  a  list  of  synonyms  which  is  appalling 
to  the  systematic  student. 

JF*.  crispata.  With  very  few  modifications,  a  description  of  P.  la- 
pillus would  apply  to  this  species,  which  occurs  commonly  at  San  Fran- 
cisco and  ranges  north.  Crispata  is  possibly  heavier,  with  a  smaller 
aperture,  and  with  four  or  five  round  teeth  upon  the  inner  white  surface 
of  the  thickened  outer  Up.  It  ranges  in  color  from  pure  white  to  dark 
brown  and  is  sometimes  banded.  The  surface  may  be  smooth  or  rough, 
and  is  sometimes  ruffled  all  over  with  wrinkled  frills.  Length  one  and 
a  half  inches.  Its  habits  and  station  are  much  the  same  as  those  of 
P.  lapillus,  of  which  it  is  possibly  a  descendant,  somewhat  modified  by 
changed  environment.     (Plate  LXXIII.) 

J*,  lima,  A  less  common  species,  with  rounded  whorls  and  channeled 
suture,  and  about  fifteen  spiral  grooves  upon  the  whorls.  The  color  is 
light  brown  ;  the  length  from  one  quarter  of  an  inch  to  one  inch. 

P,  saxicola,  A  shell  exceedingly  abundant  along  the  whole  Cali- 
fornian coast,  living  under  quite  the  same  conditions  as  the  purpuras 
already  described.  It  is  smaller  than  the  last  two,  being  always  less 
than  an  inch  in  length.  It  also  runs  through  the  gamut  of  variations  as 
to  color- scheme  and  sculpturing,  but  always  preserves  a  certain  indi- 
viduality. There  is  a  tendency  to  a  small  umbilicus ;  the  outer  Hp  is 
sharp ;  the  columella  is  flattened  and  slightly  twisted;  and  anterior  canal 
is  short,  and  bears  to  the  left.  A  smaller  aperture,  with  relatively  thicker 
shell,  seems  to  be  all  that  distinguishes  it  from  the  smaller  varieties 
of  the  east-coast  species.     (Plate  LXXIII.) 

Genus  Wonoceras 
This  genus,  which  is  very  closely  allied  to  Purpura,  is  almost 
wholly  confined  to  the  west  coast  of  the  United  States.  The 
name  is  given  on  account  of  a  peculiarity,  which  has,  however, 
already  been  noticed  in  Cerostoma,  namely,  a  horn-like  projection 
from  the  basal  portion  of  the  outer  lip.  In  all  other  respects 
this  genus  is  nothing  but  a  true  Purpura. 


388  MARINE  INVERTEBRATES 

M,  lapilloides.  The  shell  in  this  species  is  about  an  inch  in  length, 
and  has  markings  which  give  it  a  striking  resemblance  to  granite.  A 
row  of  small  round  denticles  upon  the  inner  surface  of  the  lip  is  a  charac- 
teristic already  noticed  in  some  of  the  west-coast  murices.  Their  station 
is  the  same  as  that  of  the  purpuras  —  between  the  tides  on  rocky, 
exposed  shores.     (Plate  LXXIII.) 

M,  engonatum.  This  species  has  sharply  ridged  whorls,  and  re- 
volving ribs  with  wavy  growth-lines  between  them.  In  other  respects 
it  is  almost  identical  with  the  last  described.  It  is  often  found  mingled 
with  the  seaweed  which  covers  rocks  between  tides,  and,  when  moist, 
simulates  the  color  of  its  surroundings.     (Plate  LXXIII.) 


Genus   Chorus 

C,  helcheri.  This  family  cannot  well  be  left  without  at  least  a 
mention  of  this  large  and  rather  handsome  species.  Chorus  is  a  genus 
of  but  few  species,  confined  to  the  Pacific  shores  of  North  and  South 
America.  This  particular  species  does  not  reach  as  far  north  as  San 
Francisco,  but  may  be  taken  at  low  tide  in  the  vicinity  of  San  Diego. 
The  prominent  feature  of  the  shell  is  the  posterior  canal,  which,  being 
abandoned  as  the  growth  of  the  shell  continues,  leaves  a  series  of  hol- 
low, folded  spiny  processes  upon  the  shoulder  of  the  body-whorl,  which 
appear  like  jagged  points  upon  the  spire.     (Plate  LXXIII.) 


Faivoly  columbellid^ 

This  is  a  large  family  of  small  but  often  exceedingly  beautiful 
shells.  Their  distribution  is  mostly  tropical,  but  the  list  of 
North  American  species  is  a  very  generous  one  indeed  if  the 
deeper- water  forms  are  included.  The  animal  is  quite  the  same 
as  in  the  Buccmidce,  to  be  described  later.  (See  also  description 
of  Buccinum  undatum  on  page  330.)  The  shells  are  usually  quite 
solid,  with  a  long,  narrow  slit  for  an  aperture ;  the  outer  lip  is 
thickened  on  the  inside,  especially  about  the  middle  portion,  and 
is  deeply  toothed;  and  the  lower  portion  of  the  columellar  lip 
is  also  ribbed  or  toothed. 


GrENus  Columhella 

C,  mercatoria.  This  Antillean  species  is  found  in  Florida,  and  is 
one  of  the  gems  among  the  American  shallow- water  shells.  Its  height 
is  about  one  half  of  an  inch.  It  is  decorated  with  revolving  grooves 
and  with  a  variously  patterned  color- scheme  of  broken  yellow  or  reddish 


PLATE  LXXIII. 


1,  Purpura  patula. 

2,  Purpura  crispata. 

3,  Purpura  saxicola,  enlarged. 


4,  Monoceras  lapillold.es. 

5,  Monoceras  engonatum. 

6,  Chorus  belcheri. 


PLATE  LXXIV. 

1,  Columbella  mercatoria,  enlarged.  4,  Nassa  fossata,  about  natural  size. 

2,  Columbella   (Amphissa)    corrugata,  en-      5,  Nassa  mendica,  enlarged. 

larged.  6,  Nassa  perplnguis,  enlarged. 

3,  Columbella   (Astyris)   gausapata,   much      7,  Nassa  tegula,  enlarged. 

enlarged.  8,  Sipbonalia  kellettii,  reduced. 

9,  Tritonidea  tincta. 


GASTEROPODS  389 

lines  on  a  white  background,  or  of  white  splotches  on  a  brownish  back- 
ground.    (Plate  LXXIV.) 

C,  (Anachis)  avara,  and  the  variety  C  shnilis.  These  rather 
slender  shells,  about  one  half  to  three  fifths  of  an  inch  long,  occur  from 
Florida  northward  to  Cape  Cod.  The  upper  whorls  are  smooth,  the 
lower  ones  are  undulated  with  vertical  costae  (ten  to  thirteen),  and  the 
body- whorl  is  encircled  below  the  middle  by  a  series  of  revolving,  closely 
set  grooves.  The  aperture  is  typical  of  the  genus,  though  less  strongly 
marked  by  internal  callosity  on  the  outer  lip  and  with  less  prominent 
teeth  than  in  C.  mercatoria.  The  greater  development  of  the  revolving 
grooves,  which  spread  over  the  entire  surface  of  the  body- whorl  and 
cross  the  costse,  producing  a  granulated  surface,  constitutes  the  variety 
C.  similis.  The  color  is  brownish,  with  white  reticulations.  This  species 
is  to  be  found  in  considerable  abundance  in  sandy  mud  and  among 
stones  and  algae  about  low-water  mark.  At  New  Bedford  and  Martha's 
Vineyard,  and  on  Cape  Cod,  it  may  always  be  taken.  It  is  also  common 
at  Norfolk  and  along  the  Virginia  and  Georgia  coasts. 

C,  (Astyris)  lunata.  One  of  the  characteristic  eastern-coast  shells, 
which,  like  the  last  species,  ranges  from  Cape  Ann  in  Massachusetts  to 
the  West  Indies.  It  occurs  about  low-tide  mark  and  just  below,  upon 
stones  and  algse,  or  crawling  about  on  a  soft  bottom.  On  account  of  its 
generic  features,  combined  with  the  peculiar  coloration,  the  species  can- 
not be  mistaken.  The  latter  is  a  ground  of  reddish-brown  or  fawn,  with 
encircling  rows  of  large  white  or  yellowish  spots.  The  whorls  are  quite 
smooth.     Length  not  over  one  fifth  of  an  inch. 

The  collector  soon  learns  to  recognize  the  variable  forms  of  these 
northern-range  columbellas.  They  are  not  a  difficult  group,  for  once 
their  generic  position  is  estabhshed  by  the  characters  of  the  aperture 
(which  are  constant)  the  species  can  readily  be  determined,  notwith- 
standing their  tendencies  to  vary  from  the  type.  Calif  ornian  waters  also 
have  several  columbellas.  The  conchologists  of  the  west  coast  have 
preferred  to  apply  to  their  shells,  and  indeed  to  employ  in  general  use, 
a  large  number  of  subgeneric  names  in  place  of  the  ordinarily  accepted 
generic  ones.  The  result  of  this  is  to  confuse  at  first  the  student  of 
conchology,  who,  though  fairly  familiar  with  the  molluscan  genera,  finds 
himself  perplexed  when  he  confronts  a  hst  of  west-coast  shells.  Thus 
the  two  common  Calif  ornian  columbellas  are  '^  Amphissa^^  corrugata  and 
^^  Astyris^'' gausapata,  these  two  species  belonging  to  different  subgenera 
of  the  genus  Columbella. 

C,  corrugata.  This  shell  finds  its  metropolis  in  Puget  Sound,  but 
occurs  also  along  the  CaUf ornian  shore.  The  aperture  is  wider  than  is 
usual  in  this  genus.  The  surface  is  deeply  wrinkled  by  longitudinal 
costse  and  is  encircled  by  revolving  grooves.  Length  one  half  of  an 
inch ;  color  red,  or  orange  to  light  brown.  It  is  found  in  shallow  pro- 
tected waters.     (Plate  LXXIV.) 

C  gaiisapata.  This  species  lives  in  great  numbers  about  the  roots 
of  eel-grass.  It  is  very  small  and  smooth,  with  a  rather  high  spire.  The 
color  of  the  spire  is  deep  brown ;  the  body-whorl  is  hghter  in  color.  Oc- 
casionally the  body-whorl  is  obtusely  carinated  just  below  the  suture. 
This  little  shell  is  very  common  upon  many  beaches  after  heavy  winds, 
but  it  should  be  sought  for  at  very  low  tides  and  gathered  alive.  (Plate 
LXXIV.) 


390 


MARINE  INVERTEBRATES 


Family  nassid^ 

These  are  familiar,  and  often  very  characteristic,  littoral  shells 
in  all  parts  of  the  world.  Where  they  exist  at  all  they  are  gener- 
ally to  be  found  in  astonishingly  large  numbers,  sometimes  even 
crowding  out  all  other  mollusks.  They  are  exceedingly  active 
and  predaceous,  feeding  upon  other  mollusks,  whose  shells  they 
bore  through  by  means  of  the  sharp  teeth  upon  their  lingual 
ribbon.  The  Hassidce  of  the  east  coast  find  a  relentless  enemy 
in  the  small  hermit-crabs,  which  attack  them,  drag  them  from 
their  coverings,  and  then  proceed  to  occupy  the  empty  shells 
themselves;  the  torn  and  lacerated  Nassa  animal  is  thereupon 
leisurely  eaten,  a  retribution  probably  well  deserved.  The  animal 
of  Nassa  (the  principal  genus  of  Nassidm)  is  peculiar  in  having 
frequently  a  bifurcated  tail ;  or,  to  speak  more  correctly,  the 
posterior  end  of  the  foot  is  terminated  by  two  appendices. 
It  has  a  long  siphon,  and  eyes  placed  upon  the  outer  sides  and 
near  the  base  of  the  tentacles.      The  operculum  has  serrated 

edges. 

Genus  Wassa 

N,  trivittata,  N,  obsoleta.  These  are  the  two  nassas  of  the  New 
England  and  New  Jersey  coasts.     The  first  has  a  more  northerly  range, 

extending  to  the  Gulf  of 
St.  Lawrence  ;  the  other  is 
not  usually  found  north 
of  Cape  Cod,  but  below 
that  point  as  far  as  Hat- 
teras  it  is  probably  the 
commonest  shell  of  the 
coast.  It  fairly  swarms  in 
sheltered  muddy  reaches 
about  low  tide.  Little  pools  left  by  the  tide  on  the  Jersey 
flats  are  sometimes  so  crowded  with  N.  obsoleta  that  for  lack 
of  room  the  animals  crawl  over  one  another.  N.  trivittata  is 
more  commonly  taken  at  small  depths  in  the  harbors,  where 
it  seems  to  live  well  upon  all  kinds  of  sea-bottom.  Probably 
they  exist  in  great  numbers  along  the  southern  shore  of  Long 
Island,  for  the  beaches  are  often  lined  with  their  dead  and 
worn  shells.  Over  half  the  specimens  thus  found  will  have  a 
little  round  perforation  upon  some  whorl,  showing  that  they 
were  victims  of  some  cannibalistic  brother.  The  shells  of  the 
Nassidce  have  a  short,  ovate  aperture,  with  a  short  anterior  canal.  The 
inner  lip  is  smooth,  and  is  usually  coated  over  with  a  more  or  less  heavy 


Nassa  trivittata,  showing  the  animal  as  if  crawling. 


GASTEEOPODS  391 

deposit  of  enamel.  N.  trivittata  is  about  one  half  to  seven  tenths  of  an 
inch  long,  and  is  yellowish-white.  A  series  of  revolving  grooves  cut- 
ting across  a  series  of  longitudinal  lines  gives  the  shell  a  decussated  or 
granulated  appearance.  The  whorls  are  somewhat  shouldered 
at  the  sutures,  and  are  white  inside.  N.  obsoleta  cannot  be 
called  a  handsome  shell  by  the  most  enthusiastic  collector.  Its 
spire  is  usually  eroded  or  completely  dissolved  away.  The  color 
is  blackish  to  olive,  with  the  aperture  purplish-black.  The 
columellar  lip  is  arched,  with  a  twist  or  fold  in  its  lower  portion. 
It  is  decussated  by  crossing  lines  and  grooves,  though  not  so 
conspicuously  as  N.  trivittata  ;  sutures  simple ;  length  one  half 
of  an  inch  to  one  inch.  Old  specimens  not  only  become 
eroded,  but  are  usually  covered  with  vegetable  mould,  and 
are  not  over- inspiring  to  the  collector.  They  often  live  in  brackish 
water,  and  frequent  all  the  inlets  and  marine  flats  between  Cape  Cod 
and  Hatteras.  Below  Hatteras  both  this  and  the  last-named  species 
occur,  though  not  so  plentifully. 

N.  vibex.  This  ubiquitous  little  moUusk  seems  content  in  any  station, 
and  swarms  in  all  the  sandy  bays  of  Florida.  It  is  a  busybody,  always 
on  the  move,  and  its  long  siphon  is  constantly  vibrating.  The  shell  is 
about  one  half  an  inch  long  and  shining  white,  with  brown  or 
reddish  spots.  There  are  prominent  longitudinal  undulations 
and  revolving  lines  upon  the  lower  part  of  the  body-whorl. 
The  anterior  canal  is  deeply  cut  and  very  shorty  the  colu- 
mellar lip  arched,  richly  calloused,  and  often  granulated  at  its 
base.  This  is  probably  the  fi.rst  live  shell  the  collector  in  Florida 
will  encounter.  The  animal  is  very  graceful  and  prettily 
marked  in  color.  The  terminal  cirri  on  the  foot  form  a 
notable  feature  —  a  character  belonging  to  the  entire  family, 
iV.  fossata,  JS',  perpingiiis.  On  the  Cahfornia  coast  there  are  \he 
huge  (for  this  genus)  JV.  fossata  and  the  smaller  but  no  less  interesting 
N.  perpinguis,  also  iV.  tegula  and  -^.  mendica,  N.  fossata  grows  to  a 
length  of  one  and  a  half  to  two  inches.  When  adult  the  lip  is  some- 
what thickened,  and  the  entire  aperture  is  bright  orange.  The  color  of 
the  shell  is  ashen-gray,  and  it  is  marked  with  spiral  and  transverse  riblets 
which  produce  a  granulated  surface,  especially  upon  the  upper  whorls. 
The  shell  is  ribbed  inside  the  mouth.  A  deep  groove  circles  the  anterior 
canal  at  the  base  of  the  body-whorl.  N.  perpinguis  is  an  especially 
graceful  shell,  smaller  than  the  last-named  and  more  finely  decussated 
and  darker  (brown)  in  color.  It  also  has  a  deeply  channeled  groove 
encirchng  the  base  of  the  body-whorl.  It  is  often  banded  in  chestnut. 
Both  these  species  occur  in  the  southern  part  of  Cahfornia  only;  N. 
tegula  and  N.  mendica  are  of  more  northern  range.  The  former  resem- 
bles the  Floridian  N.  vibex.  N.  mendica  is  a  slender  shell  three  quar- 
ters of  an  inch  long,  with  prominent  longitudinal  ridges,  and  light  brown 
in  color,  with  a  white  aperture.     (Plate  LXXIV.) 

Family  BUCCiNiD.a: 
From  the  number  of  subfamilies  and  genera  included  in  this 
exceedingly  large  and  comprehensive  family,  it  would  almost 


392 


MARINE  INVERTEBRATES 


seem  that  it  has  served  as  a  sort  of  dumping-ground  for  various 
groups  of  moUusks  of  uncertain  biological  affinities.  Although 
the  family  has  recently  been  reduced  by  the  removal  of  several 
large  families,  it  still  remains  a  bulky  one. 

Genus  JBuccinuiu 

The  animal  is  described  at  some  length  on  page  330.  It  has 
no.  striking  peculiarities.  The  siphon  in  Buccinum  is  fairly  long ; 
the  eyes  are  placed  about  midway  between  the  base  and  the  end 
of  the  tentacles.  It  is  in  general  a  conventional  prosobranch  ani- 
mal. The  great  majority  of  the  members  of  this  family  have  a 
boreal  range  and  are  found  widely  distributed  within  the  colder 
waters  of  the  world. 


B,  undatum.     This  is  the  most  prominent  representative  of  the 
Buccinidce  upon  the  North  Atlantic  shores  of  the  United  States.     It  is  an 

exceedingly  common  shell,  ranging  from 
Cape  Cod  to  Greenland.  It  is  also  found  in 
England  and  Scotland,  where  it  is  exten- 
sively used  as  food  under  the  familiar  name 
of  '^  whelk."  It  affects  every  kind  of  station 
and  seems  to  be  as  much  at  home  in  very 
considerable  depths  as  about  the  low-tide 
mark.  Upon  the  Maine  coast  it  may  be 
found  almost  everywhere,  just  below  low 
tide.  If  none  are  in  sight  they  may  be  at- 
tracted by  putting  a  dead  fish  in  a  basket 
and  anchoring  it  near  shore.  The  American 
whelk  is  somewhat  smaller  than  the  British 
variety,  although  it  attains  a  length  of  full 
three  inches.  It  has  revolving  ribs  and 
longitudinal  oblique  folds.  A  yellowish- 
brown,  velvety  epidermis  covers  the  entire 
shell.  The  lip  is  simple,  and  the  shell  is 
white  or  golden  yellow  within.  The  colu- 
mella is  somewhat  twisted;  the  operculum 
is  corneous,  with  a  lateral  nucleus.  The 
variations  in  this  shell  are  so  great  as  to 
have  caused  naturalists  no  little  perplexity.  Specimens  taken  near 
large  cities  are  apt  to  be  defective.     (Plate  I.) 


Buccinum  undaium. 


Genus  ChrysodoTnus 

C.  decemcostatus.    One  of  the  most  striking  shells  of  our  northeast 
coast.    As  its  name  indicates,  it  is  decorated  with  (normally)  ten  costse. 


GASTEROPODS 


393 


These  are  prominent  revolving  ribs  or  keels  upon  the  body-whorl,  the 
upper  one  being-  the  largest,  the  others  diminishing  in  size  toward  the 
base  of  the  shell.  Upon  the  upper 
whorls  but  two  of  these  circling 
keels  appear.  The  lip  is  plain,  but 
somewhat  modified  by  the  termi- 
nation of  the  ribs.  The  columella 
is  arched  above ;  the  canal  pro- 
duced (sometimes  to  the  left).  The 
color  without  is  dull  ashen- white 
to  horn  j  within,  pure  white.  The 
operculum  is  small,  with  a  termi- 
nal nucleus.  The  animal  is  the 
same  as  Buccinum.  This  species 
is  not  quite  so  common  as  B.  undci- 
tum,  but  it  is  often  found  asso- 
ciated with  it.     At  Eastport  and 


Chrysodomus  decemcostatiis. 

Bar   Harbor    it  is    abundant 
below  low-water  mark. 


just 


Sipho  Stimpsoni. 


Genus  Sipho 

S,  stimpsoni.  One  of  the  most 
graceful  of  the  larger  shells  of  our 
eastern  coast.  It  is  almost  identical 
with  the  S.  islandicus  of  northern 
European  waters,  and  for  a  long  time 
was  considered  to  be  the  same  species. 
S.  Stimpsoni  is  not  found  south  of 
Cape  Cod,  except  possibly  in  deep 
offshore  stations.  North  of  that  point 
it  ranges  to  Newfoundland,  but  it 
has  enjoyed  the  reputation  of  being 
a  rare  shell  and  has  been  greatly 
prized  by  local  collectors  in  conse- 
quence. It  is,  in  fact,  not  rare  to 
any  one  who  is  provided  with  a  dredge 
and  rope  enough  to  enable  him  to  use 


394  MARINE   INVERTEBRATES 

it  effectively  in  from  twenty  to  one  hundred  feet  of  water.  The  spire  is 
high  and  regular,  with  seven  to  eight  slightly  rounded  whorls.  The  suture 
is  simple,  and  there  are  faint  revolving  grooves.  The  epider- 
mis is  thick,  horn-colored,  and  sometimes  velvety;  the  lip 
simple ;  and  the  anterior  canal  produced.  The  shell  is  pure 
white  within.  The  operculum  is  corneous,  with  a  subterminal 
nucleus.  The  animal  is  the  same  as  Buccinum,  but  with 
small  irregular  specks  of  black.  This  shell  is  found  from  three 
to  five  inches  long. 

^*  pygmceus.     This  species  has  the  same  range  as  that  of 
the  species  just  described,  and  often  occurs  associated  with 
^  the  young  of  the  latter.      It  may  be  distinguished  from  aS'. 

pyomceus.      Stwipsoni  by  the  greater  number  of  whorls,  the  more  promi- 
nent revolving  ridges,  and  the  smaller  aperture.      The  epi- 
dermis is   drab-colored  and  strongly  corrugated,  inclined  to  hirsute. 
The  color  of  the  shell  is  pure  white.     Length  one  inch  to  one  and  a  half 
inches.    It  is  found  from  low-tide  mark  to  very  considerable  depths. 

Genus  Sij^honalia 

S.  kellettii,  Siphonalia  is  one  of  the  Pacific  genera  of  the  Buccinidce, 
which  finds  its  greatest  development  in  Japanese  waters.  One  of  these 
Japanese  species,  S.  'kellettii,  is  also  found  in  California.  It  has  the  typical 
animal  of  the  BuccinidcB,  and  a  fusiform  shell  white  to  brownish  in  color, 
and  three  to  five  inches  in  length.  It  is  conspicuously  marked  upon  the 
whorls  by  a  revolving  series  of  large  rounded  knobs  and  indistinct 
revolving  grooves.  The  operculum  is  corneous,  the  nucleus  subterminal. 
It  is  found  in  shallow  water  to  low-tide  mark.     (Plate  LXXIV.) 

Genus  Tritonidea 

T,  tincta,    A  Floridian  species  which  ranges  from  Hatteras  to  the 

West  Indies,  and  finds  its  station  near  low-tide  mark,  upon  coralline 
rock  or  rough,  stony  bottom.  It  is  about  one  inch  in  length,  is  of  a 
brownish  horn-color,  and  has  an  oval  aperture  with  a  crenulated  outer 
lip  and  a  deep  anterior  canal.  An  entering  ridge  of  white  enamel  at 
the  top  of  the  columellar  lip  forms,  with  one  of  the  teeth  of  the  outer 
lip,  a  posterior  canal.  It  is  sculptured,  with  revolving  ridges  and  cross- 
ing longitudinal  folds.  The  color  is  bluish-white  within  the  shell,  touched 
with  yellow  about  the  anterior  canal  and  along  the  edge  of  the  outer  lip. 
(Plate  LXXIV.) 

Family  xuRBmELLiD^ 
Genus  Fulgur 
Of  the  two  genera  of  this  family  which  occur  in  American 
waters,  Fulgur  may  be  taken  as  the  most  characteristic  moUusk 
of  the  American  Atlantic  fauna;  that  is  to  say,  FuJgur  occurs 
only  on  the  American  east  coast.  Its  range  is  from  Cape  Cod  to 
the  West  Indies.     The  two  Northern  species  are  F.  carica  and 


GASTEROPODS 


395 


F.  canaliculafa,  both  of  which  are 
exceeding^  common  in  sandy 
shore  stations  from  Cape  Cod 
southward. 

F,  carica.  The  largest  univalve 
north  of  Hatteras,  most  easily  rec- 
ognized by  its  pear-shaped  shell,  with 
simple  suture  and  brilliant  vermilion 
aperture.     The  anterior  canal  is  long 


Fulgur  carica. 

and   open ;   the    columellar   lip    is 
twisted  and  arched,  and  the  outer 
lip  is  simple.     There  is  a  revolving 
row  of  nodes   or  spines    of  various   degrees  of 
prominence  upon  the  shoulder  of  the  body-whorl, 
continued  on  the   spiral  whorls  just  above  the 
suture.     The  color  varies  from  ashen-gray  to  a 
dirty  brown.      In    young    specimens  there    are 
stripes  and  bands  of  violaceous  brown,  and  the 
shells  are  striate  within  the  aperture.     The  length 
of  this  shell  is  sometimes  nine  inches. 
Fuicjur  canaiicuiata.  F.  carica  frequcnt^s  almost  any  sort  of  bottom. 

In  Long  Island  Sound  they  are  common  on  stony 
ground,  but  they  do  not  attain  the  maximum  size  and  the  high  degi-ee  of 
aperture-coloration  characteristic  of  those  taken  along  the  New  Jersey 
shore,  on  sandy  stations  exposed  to  the  surf.  The  string  of  curiously 
shaped  capsules  containing  the  eggs  of  Fulgur  is  shown  in  Plate  I. 

F,  canaiicuiata  often  occurs  associated  with  the  last.     It  does  not 
attain  quite  the  same  size,  but  specimens  of  both  species  are,  on  the 


396  MARINE  INVERTEBRATES 

average,  about  equal  in  cubic  capacity.  It  is  pear-shaped,  like  F.  carica, 
and  has  a  long  anterior  canal ;  but  its  distinguishing  features  are  the 
flattened  shoulder  of  the  whorls  and  the  deeply  channeled  sutures.  The 
epidermis  is  brown,  thick,  and  heavy.  The  color  of  the  sheU  is  whitish- 
gray,  yellowish  within.  It  is  found  in  the  same  places  as  F.  carica,  and 
is  very  abundant  at  Atlantic  City  and  along  the  entire  New  Jersey 
coast. 

F.  pert'ersa.  A  Floridian  species,  immediately  recognizable  by  the 
fact  that  it  is  sinistral ;  otherwise  a  description  of  the  shell  would  almost 
fit  that  of  F.  carica,  except  in  the  matter  of  the  color  of  the  aperture, 
which  in  F.  perversa  is  brownish-white.  The  brownish  streaks  upon  the 
whorls,  in  young  specimens,  are  a  very  noticeable  feature  of  this  shell. 
The  shoulders  of  the  whorls  are  rather  flatter  than  in  F.  carica,  but, 
unlike  F.  canaliculata,  the  sutures  are  simple.  The  row  of  nodes  or 
rounded  spines  which  encircles  the  body-whorl  appears  in  the  spire  as 
nodes  just  above  the  sutures.  The  animal  is  jet-black,  and  frequents 
sandy  flats,  where,  at  low  tide,  it  may  be  gathered  in  considerable  num- 
bers, as  it  plows  its  way  along,  almost  wholly  concealed  beneath  the  sand. 
Large  specimens  measure  quite  a  foot  in  length.  In  old  shells  the 
color-markings  are  not  so  briUiant,  the  shells  being  a  dull,  lusterless 
white.     (Plate  LXXV.) 

F,  pyriim.  Another  Floridian  species,  much  smaller  than  the  last 
(three  to  four  inches),  with  a  regular,  pear-shaped  outline,  a  long  ante- 
rior canal,  a  low  spire,  deeply  channeled  sutures,  flattened  shoulders,  and 
no  spinous  or  nodose  processes.  It  is  ornamented  with  revolving  incon- 
spicuous ribs  or  striae,  alternately  larger,  and  has  a  somewhat  hirsute 
epidermis.  The  color  is  white,  with  transverse  broad  yellowish  or  rusty 
lines  J  the  color  within  the  aperture  resembles  that  of  the  exterior  color- 
lines.     It  is  found  on  sandy  stations,  in  shallow  water.     (Plate  LXXV.) 


Genus  Melongena 

M.  corona,  A  Floridian  species,  named  from  the  single  or  double  row 
of  spinous  processes  upon  the  shoulder  of  the  body- whorl  and  the  crenu- 
lated  appearance  of  the  spire  caused  by  the  continuations  of  the  triangu- 
lar spines.  The  three  apical  whorls  are  not  spinous.  There  is  also  a 
row  of  hollow  triangular  spines  obliquely  encircling  the  base  of  the  shell. 
The  epidermis  is  heavy,  rough,  and  brown  5  the  aperture  oval  and  large ; 
the  outer  lip  notched  at  points  where  the  spines  commence  ;  the  anterior 
canal  wide  and  short ;  and  the  columella  white  and  twisted,  and  banded 
within  with  purplish- chestnut  and  white.  The  color  without  is  drab  in 
older  specimens,  in  young  specimens  chestnut  banded  with  revolving 
striae.  Length  four  inches.  Found  in  shallow  water.  This  active  pre- 
daceous  animal  must  be  the  terror  of  the  mollusks  in  Florida.  With  his 
sharply  toothed  radula  he  is  able  to  pierce  even  the  ponderous  clam- 
shell, Venus  mercenaria,  variety  mortoni,  and  devour  the  soft  fleshy  parts 
within.  No  mollusk,  save,  perhaps,  the  vigorous  Strombus  pugilis,  can 
escape  the  attack  of  this  highwayman.     (Plate  LXXV.) 


GASTEROPODS  397 

Family  fasciolaeud^ 

This  family  comprises  a  number  of  genera  of  mollusks  which 
have  a  fusiform  shell,  with  a  long-drawn-out  spire  and  a  long 
anterior  canal.  The  animal  is  in  no  manner  remarkable;  no 
essential  differences  are  to  be  noted  from  the  usual  conventional 
type  of  gasteropod  mollusk,  represented  in  the  two  families  last 
described. 

Genus  Fasciolaria 

This  genus  is  of  tropical  range,  and  contains  many  species  of 
shells  which  are  more  or  less  conspicuous  for  their  large  size  or 
their  beauty  of  form.  Three  species  occur  in  Floridian  waters,  and 
all  of  them  may  be  taken  about  low-tide  mark  on  the  sandy  flats 
which  are  so  characteristic  of  Florida  bays  and  harbors.  All  of 
them  are  sluggish  animals  which  crawl  very  slowly  along  the 
bottom  or  bury  themselves  almost  wholly  in  the  sand,  leaving  only 
the  tip  of  the  spire  projecting  slightly  above. 

F,  gigantea.  This  is  said  to  be  the  largest  gasteropod  shell  known .  It 
often  attains  a  length  of  sixteen  inches,  and  specimens  are  reported  to 
have  been  found  measuring  no  less  than  two  feet.  This  huge  moUusk 
has  a  symmetrically  fusiform  shell,  with  whorls  obtusely  ridged  and 
armed  with  large  rounded  nodes.  The  aperture  is  reddish-brown  within. 
The  anterior  canal  is  long  and  open,  and  there  are  three  ''  plaits,"  or 
folds,  about  the  columella.  The  outer  lip  is  more  or  less  sinuate,  the  color 
is  fleshy-white,  and  the  shell  is  covered  with  a  thick  yeUowish  or  chestnut 
epidermis.    The  animal  is  of  a  brilliant  scarlet  color.     (Plate  LXXVI.) 

F,  tulipa.  An  exceedingly  common  species  of  Floridian  waters,  which 
may  justly  be  classed  among  the  '^  show  shells  "  of  the  American  Atlantic 
fauna.  It  has  a  typically  symmetrical,  fusiform  shape,  with  gracefully 
rounded  whorls,  and  is  spirally  but  not  deeply  grooved.  The  sutures  are 
crenulated;  the  anterior  canal  is  long;  there  are  three  entering  folds 
upon  the  columella ;  and  the  outer  lip  is  simple.  The  scheme  of  coloration 
is  variable,  but  there  are  two  chief  patterns,  which  are  usually  followed, 
though  they  often  are  considerably  modified.  One  is  a  light-bluish  body, 
variegated  with  chestnut  or  olive  blotches,  which  "are  more  extensive 
upon  the  spire  than  upon  the  body-whorl ;  the  other  is  a  pinkish  body, 
encircled  with  revolving  black  lines.  The  specimens  of  F.  tulipa,  which 
are  found  so  abundantly  in  the  shallow  bays  and  estuaries  of  the  Florida 
coast,  are,  for  some  reason,  never  brightly  colored,  as  are  those  taken  in 
the  open  sea.     The  length  is  about  four  to  six  inches.     (jPlate  LXXVI.) 

F.  distans,  A  form  almost  identical  with  that  last  described.  It  is 
much  smaller,  varying  from  two  to  three  inches  in  length,  lacks  the  cren- 
ulations  of  the  sutures,  and  is  perfectly  smooth,  save  for  a  few  spiral 
ridges  about  the  base.     The  color  is  bluish-white,  with  clouded  longitu- 


398 


MARINE  INVERTEBRATES 


dinal  streaks  of  olive.     Encircling  the  shell  are  from  four  to  seven  black 
lines.     (Plate  LXXVI.) 

These  three  species  of  Fasciolaria  often  occur  associated  upon  sand- 
banks which  are  exposed  at  unusually  low  tides.  It  requires  some  force 
to  dislodge  the  large  F.  gigantea  from  its  bed  of  sand.  When  the  apex 
is  discovered  projecting  an  inch  or  less  from  the  bottom ^  the  collector 
must  scrape  away  the  sand  down  to  the  body- whorl,  and  then  secure  a 
good  hold  upon  the  spire  and  pull  hard.  The  stupid  animal  will  not  at 
once  withdraw  into  his  shell,  but  will  hang  protruded  from  the  aperture 
like  a  great  piece  of  vividly  red  meat.  To  extract  any  of  these  larger 
fasciolarias  from  its  shell,  it  is  necessary  to  boil  it  for  ten  or  fifteen  min- 
utes. Large  specimens  of  F.  gigantea  should  remain  in  the  pot  half  an 
hour.  The  heavy  corneous  epidermis  of  F.  gigantea  will  dry  and  crum- 
ble away  unless  it  is  rubbed  with  vaseline  about  once  a  year. 


Family  volutid^ 

Genus  Valuta 

The  Volutidae,  like  the  cowries,  are  ^'  aris- 
tocratic" shells.  As  was  stated  above, 
there  are  many  collectors  who  have  be- 
come so  fascinated  by  the  shells  of  a  few 
of  these  ' '  first  families  of  the  Mollusca ''  that 
they  make  great  efforts  and  spend  no  small 
sums  in  seeking  to  complete  their  cabinet 
series  of  the  rare  and  morebeantifnl  forms. 
The  Volutidce  certainly  have  very  beauti- 
ful shells,  and  they  are  for  the  most  part 

J  HIJIH  0  ^'  MlWI/i     exceedingly  rare.     The  reason  of  their 

ilFilliil  ^  ^A  Wllilll/mi      rarity  has  no  doubt  something  to  do  with 

their  habits.  They  are  probably  largely 
dwellers  npon  rocky  ground,  where  the 

\  ii\ '   \ii^  W^/M  dredge  cannot  reach  them.     There  is  but 

|*^^HP  m  one  species  of  Yoluta  upon  the  American 

'•►^^''^^fcjf  coasts  which  is  available  to  the  shore-col- 

A — .^^1^]  lector,  and  this  is  the  well-known  and 

much-songht-after  V.junonia,  The  ani- 
mal of  Yoluta  has  a  very  broad  foot,  and 
a  head  curiously  divided  into  two  lobes, 

upon  which  are  placed  sessile  eyes.     A  remarkable  feature  of  the 

genus  is  the  lack  of  an  operculum. 


I 


Iv 


Valuta  junonia. 


GASTEROPODS  399 

V,  Junonia,  This  volute  lias  never  been  taken  alive  in  shallow  water 
near  the  shore,  but  is  occasionally  found  cast  upon  the  beach  after  vio- 
lent storms.  Sanibel  Island  is  the  best  locality.  V.  junonia  has  an 
obtuse  apex,  a  long  aperture,  and  a  shell  from  three  to  three  and  a  half 
inches  in  length.  The  color  is  cream- white,  painted  with  rows  of  large 
deep-red  spots.  In  his  "American  Marine  Shells,"  published  nearly 
thirty  years  ago,  Mr.  Try  on  says:  "  This  is  the  most  rare  and  valuable 
American  marine  shell ;  specimens  in  good  condition  sell  for  from  fifty  to 
one  hundred  dollars."  A  good  specimen  is  probably  not  worth  so  much 
to-day  as  when  Mr.  Try  on  wrote,  but  it  is  at  least  worth  a  careful  survey 
of  a  Floridian  beach  after  a  storm. 

Family  maeginellid^ 

Genus  Marginella 

This  is  a  family  of  exquisite  little  shells.  In  point  of  beauty 
they  would  rival  the  volutes  were  they  not  so  much  handicapped 
by  their  small  size.  The  largest  Marginella  is  not  more  than  an 
inch  and  a  half  in  length,  while  the  great  majority  of  its  two  hun- 
dred tropical  species  do  not  exceed  one  half  an  inch.  The  animal 
is  very  similar  to  that  of  Volufaj  indeed,  the  margineUas  were 
until  recently  included  in  the  VoluUdce.  The  shell  is  also  sug- 
gestive of  Voluta.  It  is  porcelanous,  highly  polished,  and  shin- 
ing like  all  shells  which  are  covered  by  a  portion  of  the  mantle 
when  the  animal  is  extended.  Forty-seven  species  of  Marginella 
are  recorded  from  the  Atlantic  coast  of  the  United  States.  The 
margineUas  frequent  sandy  or  muddy  sheltered  spots,  and  may  be 
collected  between  tide-marks.  In  California  there  are  several 
species,  which  are  so  minute  that  it  seems  hardly  worth  while  to 
attempt  a  description  of  them.  They  are  white  and  very  incon- 
spicuous little  shells.  One  is  tempted,  however,  to  speak  of  some 
of  the  fine  margineUas  of  the  Bahamas.  The  animals  are  quite 
as  beautifully  marked  as  the  shells  themselves,  while  the  shell  of 
one  species  is  used  in  jewelry  on  account  of  its  pearly  luster  suf- 
fused with  the  most  delicate  pink. 

M.  apicina.  The  most  abundant  Floridian  species  of  this  genus. 
It  is  not  more  than  one  third  of  an  inch  long,  with  a  depressed  spire,  a 
large  body- whorl,  a  long  aperture  nearly  equaling  the  entire  length  of 
the  shell,  a  thickened  outer  lip,  and  four  very  prominent  plaits  on  the 
columella.  The  surface  is  smooth.  The  white,  enlarged  outer  lip  is 
glazed  or  highlv  polished,  and  bluish  or  brown  in  color,  with  red  spots. 
(Plate  LXXVII.) 


400  MARINE  INVERTEBRATES 

Family  olivid^ 

Genus   Oliva 

The  genus  Oliva  is  one  of  the  favorites  among  collectors.  It 
comprises  smooth,  highly  polished,  porcelanous,  and  oval  shells 
with  a  deeply  notched,  long,  narrow  aperture.  The  columellar  lip  is 
usually  heavily  calloused  and  ornamented  with  oblique  folds.  The 
animal's  foot  is  very  large,  and  extends  laterally  into  lobes  which 
curve  back  over  the  shell.  In  front  the  propodium  is  very  large, 
forming,  as  in  Natica  and  Polymces,  a  sort  of  plow.  The  mantle 
lobes  almost  cover  the  shell  when  extended. 

O.  literata.  The  only  American  example  out  of  some  sixty  known 
species.  It  is  found  in  great  abundance  in  sandy  tide-pools  along  the  west 
Florida  shores.  It  ranges  from  Hatteras  to  the  West  Indies,  and 
may  be  looked  for  in  stations  similar  to  those  of  the  naticas.  It  is  ex- 
ceedingly active,  crawhng  rapidly  over  the  sand  or  burying  itself  very 
quickly  out  of  sight,  and  is  carnivorous.  The  shell  is  highly  polished, 
about  two  inches  long,  and  pale  yellowish- white  in  color,  covered  with 
longitudinal,  angulated,  or  zigzag  lines  of  chestnut.  The  spire  is  short, 
the  sutures  channeled,  and  the  columella  calloused  with  white  enamel, 
and  obliquely  striated.     (Plate  LXXVII.) . 

Genus   Olivella 

The  genus  Olivella  resembles  Oliva  very  closely  in  conchologi- 
cal  characters,  but  the  shells  are,  with  few  exceptions,  exceed- 
ingly small,  and  usually  have  a  somewhat  more  elongated  spire 
than  is  the  case  in  the  genus  Oliva  proper.  The  animal  of  Oli- 
vella seems  to  be  a  degenerate,  for  it  possesses  neither  tentacles 
nor  eyes.     In  habit  and  station  it  resembles  Oliva, 

O.  mutica.  In  Floridian  waters  this  species  is  exceedingly  common. 
It  is  not  more  than  one  fifth  of  an  inch  long,  is  highly  polished  and  shin- 
ing, and  yellowish- white  in  color,  with  revolving  pale  rufous  bands.  It 
has  the  typical  oliva-shape. 

O.  bipUcata,  A  Californian  species  of  considerable  interest,  the 
largest  of  the  olivellas.  It  was  evidently  used  by  the  aborigines  as 
wampum  or  as  ornaments,  for  a  great  many  specimens  are  found  among 
buried  Indian  relics.  This  species  is  about  the  size  and  shape  of  an 
olive.  The  spire  is  short,  though  longer  than  the  typical  Oliva  spire,  the 
shell  is  smooth  and  highly  polished,  and  the  columella  is  thickly  cal- 
loused, and  has  two  entering  folds  near  the  base.  The  color  is  creamy- 
white  to  dove-color,  with  a  purple  sheen  over  all,  and  purple  markings 


PLATE   LXXVII. 


1,  Marginella  apicina,  enlarged.  3,  Olivella  biplicata,  enlarged. 

2,  Oliva  literata.  4.  Conns  floridanus. 

5,  Cancellaria  reticulata. 


GASTEROPODS  401 

about  the  base.  Professor  Keep  speaks  of  the  vast  numbers  of  these 
olivellas  on  sandy  stations  along  the  Pacific  coast.  Having  found  a  place 
where  a  "  little  stream  of  water  was  oozing  out  from  the  bank  of  sand," 
he  proceeded  to  dig  with  a  hoe.  ''  I  found  them  [0.  hiplicata]  by  the 
hundreds,"  he  continues,  ^'  and  I  had  gathered  about  a  thousand  before 
the  tide  came  in.  They  seemed  to  lie  in  groups  just  under  the  surface 
of  the  sand,  yet  wholly  concealed  from  sight."     (Plate  LXXVII.) 

O.  boetica,  A  much  smaller  Pacific  form,  with  a  higher  tapering 
spire.  It  is  brown  to  bluish  in  color,  and  often  has  yellowish  stripes.  It 
is  polished  and  shining.     Found  in  sandy  stations. 

Family  conid^ 

Genus   Conus 

This  is  a  comprehensive  family  of  several  highly  diversified 
genera.  Its  most  prominent  genus  is  Conus,  a  name  which  indi- 
cates the  principal  feature  of  the  shell,  for  it  is  almost  an  exact 
cone  in  shape.  Conns,  along  with  Yolufa  and  Cyprma,  is  entitled 
to  the  honor  of  being  considered  an  aristocrat  among  mollusks. 
There  are  about  three  hundred  and  fifty  species  known,  mostly 
tropical  and  Indo-Pacific  in  distribution.  The  shells  have  many 
points  of  beauty  and  are  often  of  very  high  coloration  and  ec- 
centric markings.  Some  of  the  rarer  forms  are  famous  in  con- 
chological  annals  for  the  enormous  prices  which  they  have 
commanded.  The  rare  and  beautiful  Conus  gloria-maris  once 
brought  £43  ($215)  at  an  auction  sale  in  London.  In  all  shells  of 
Conus  there  is  a  notch  at  the  upper  edge  of  the  aperture  for  the 
accommodation  of  a  posterior  canal.  In  some  other  genera  of 
this  family  this  notch  becomes  a  more  prominent  feature.  The 
animal  has  a  well-developed  foot,  a  retractile  proboscis,  eyes 
situated  upon  the  tentacles,  and  a  fairly  long  siphon.  Upon  the 
under  surface  of  the  foot  is  a  conspicuous  pore,  which  opens  into 
a  water- vascular  system  of  the  foot.  Conus  is  accused  of  having  a 
poison-gland  connected  with  the  radula  and  of  having  shown 
vicious  traits  when  captured.  The  animals  are  shy,  and  remain 
most  of  the  time  in  hiding,  while  their  pretty  shells  during  life 
are  generally  rendered  obscure  by  a  dull,  colorless  epidermis. 
There  are  but  few  species  of  Conus  upon  the  Atlantic  shores  of 
the  United  States,  and  these  are  confined  to  the  warmer  waters 
of  Florida  and  the  Gulf  of  Mexico. 

26 


402  MARINE  INVERTEBRATES 

C.  fioridanus,  A  not  unusual  sheU  in  shallow- water  stations 
throughout  the  Florida  coast.  It  has  almost  the  exact  outlines  of  a  cone. 
The  flattened  shoulder  is  marked  off  by  an  acute  carina  ;  the  spire  is  low, 
bat  many-whorled  and  pagoda-like ;  the  aperture  is  long  and  narrow, 
and  the  lip  is  simple.  The  coloring  is  yellowish,  banded  on  a  creamy- 
white  background,  or  dotted  in  circular  rows.  Length  two  inches. 
(Plate  LXXVII.) 

C  pealii.  One  of  the  smallest  species  of  this  genus,  its  length  never 
exceeding  one  half  of  an  inch,  whereas  the  majority  of  the  cones  are  over 
two  inches  in  length,  and  many  of  them  rank  as  large  shells.  This  little 
Floridian  species  is  regularly  cone-shaped,  with  carinated  whorls,  thin 
outer  hp,  and  pagoda-like,  low  spire.  The  color  is  reddish-brown  with 
sky-blue  spots,  or  bluish-brown  with  lighter  spots.  There  are  encircling 
grooves  about  the  base  of  the  shell. 

Family  cancellariid^ 
Genus    Cancellaria 

The  last  family  of  the  Gasterojjoda  to  be  considered  is  the  Cancel- 
lariidcB,  v^hich  has  but  one  genus,  Cancellaria,  There  are  several 
species  upon  the  east  coast  belonging  to  deeper-water  zones,  but 
one  well-known  species,  C,  reticulata,  is  very  common  on  shore 
stations  from  Hatteras  south.  The  shell  is  oblong  and  solid, 
with  a  moderate  spire,  and  whorls  slightly  flattened  below  the 
sutures,  and  is  very  roughly  granulated  or  reticulated.  The 
aperture  is  narrowly  ovate,  and  is  ribbed  inside.  The  columella 
has  two  very  strong  and  prominent  plaits.  The  color  is  white, 
banded  and  variegated  with  reddish-brown.  Length  an  inch  or 
more.     (Plate  LXXVII.) 

CLASS  SCAPHOPODA 

Family  DENTALiD.ffi 

in  nearly  all  collections  of  shells  from  the  northeast  coast  of 
the  United  States  are  certain  specimens  about  one  to  one  and 

a  half  inches  long,  pure  white,  and 
shaped  very  much  like  an  elephant's 

Entalis  striolata.  ^^^^        rpj^^^  ^^^   TOUUd,   holloW   tubcS, 

slightly  curved,  of  larger  diameter  at  one  end  than  at  the  other, 
and  with  an  opening  at  either  end.  There  are  two  very  common 
species  of  these  tooth-sheUs  upon  the  New  England  coast,  Deiv- 


GASTEROPODS 


403 


talium  dentate  and  Entails  striolata.  The  first  has  a  simple  round 
hole  at  the  smaller  end  of  the  shell,  and  is  faintly  marked  by  longi- 
tudinal striae ;  the  other  is  a  smooth  shell  which  has  a  notch-like 
fissure  on  the  margin  of  the  apical  perforation.  Neither  of  these 
species  is,  strictly  speaking,  a  littoral  form,  for  all  the  Dentalidce 
range  into  deep  water,  many  of  them  living  only  in 
the  profounder  depths  of  the  ocean.  But  these  two 
species  are  exceedingly  common  in  the  New  England 
coastal  waters,  at  very  moderate  depths,  and  may 
sometimes  be  found  upon  the  beach  cast  up  by  storms. 
They  live  buried  in  the  mud,  and  feed  upon  inf usorians 
and  all  manner  of  microscopic  organisms. 

Upon  the  west  coast  Dentalium  pretiosum  is  very 
abundant  north  of  California.     It  is  almost  like 
the   east-coast   Benfalium,  but  is  more  slender. 
The  Indians  used  to  gather  these  shells  and  string 
them  together  upon  long  threads  to  be  carried 
about  and  used  as  money.      In  Cahfornia  oc-    q- 
curs  Dentaliutn  hexagonum,  a  very  delicate 
little  species  with  a  slightly  angulated  shell. 

The  animal  of  the  Dentalidce  is  remark-  'p. 
able,  and  easily  merits  the  rank  of  a  sepa- 
rate molluscan  class.  It  has  no 
head,  no  tentacles,  no  eyes,  no 
heart,  and  no  gills.  It  is  a  mol- 
lusk  because  it  has  a  mantle,  a 
foot,  and  a  radula.  Its  position, 
therefore,  is  between  the  Gas- 
teropoda, which  it  resembles  in 
its  univalve  shell  and  radula,  and 
the  Felecijpoda,  to  which  it  is  related  by  the  pointed  foot  and 
the  absence  of  head  and  tentacles,  and  also  by  the  symmetry 
which  pervades  its  organization. 

Upon  either  side  of  the  mouth,  just  beneath  the  flap  of  the 
mantle,  are  bunches  of  ciliated,  contractile  filaments  {captacula), 
flattened  at  the  end,  which  are  supposed  to  be  breathing-organs, 
and  are  perhaps  exserted  for  the  purpose  of  catching  food. 


Dentalium,  as  seen  in  longitudinal  section  (ex- 
cept the  foot) :  S,  shell ;  Mt,  mantle ;  Sm,  shell 
muscle  ;  Mh,  mantle-cavity ;  F,  foot ;  Mk,  ce- 
phalic prominence  or  oral  cone  ;  T,  captacula  ; 
B,  radula  ;  D,  intestine  ;  L,  liver  ;  Af,  anus  ;  G, 
cerehral  ganglion  ;  N,  kidney ;  Ge,  generative 
gland. 


404  MARINE   INVERTEBRATES  ^ 

The  entire  absence  of  such  important  organs  as  the  heart  and 
gillSj  together  with  the  fact  that  they  are  undoubted  moUusks, 
would  indicate  that  the  ^capliopoda  are  very  degenerate  animals. 
The  circulatory  and  respiratory  system  of  moUusks  is  typically 
of  a  high  order. 

A  great  many  specimens  of  the  Bentalidm  dredged  in  New 
England  waters  are  dead  shells,  occupied  by  a  worm  which  seals 
up  the  larger  opening,  leaving  only  a  small  aperture  through 
which  it  protrudes  its  long  white  body.  These  must  not  mislead 
the  collector  into  a  vain  search  for  a  mantle  and  other  moUuscan 
characteristics  of  anatomy. 

Some  of  the  larger  species  of  Dentalium  from  deep-sea  stations 
are  four  to  five  inches  in  length. 


TABLE  OF  THE  COMMONER  NORTH  AMERICAN  PELECYPODS 
DESCRIBED  IN  THIS  CHAPTER 

Class 

PELECYPODA 


Orders  Families 

PROTOBKANCHIATA 

NUCULID^ 


Genera 


rNucida 
I  Leda 


\ 


Yoldia 


SOLENOMYID^      Soleiiomya 
FILIBBANCHIATA 


Anomia 


ANOMIID^ 


^  Flacunanomia 
ARCiD^      Area 


MYTILID^ 


Mytilus 


Modiola 


FSEUDOLAMELLIBRANCHIATA 

rAvicula 

AVicuLiD^  <  Pinna 

Kperna 

OSTREID^      Ostrea 


PECTiNiD^      Pecten 


Species 

]^,  proxima 
L,  tenuisulcata 
Y,  limattda 
Y,  thraciceformis 
Y,  sapotilla 
S,  velum 
S,  borealis 

A,  simplex 
A,  aeuleata 
A,  lampe 
P»  macrochisma 
A,  ponderosa 
A.  now 
A.  pexata 
M.  edulis 
M,  hamatus 
M.  ealifornieus 
M,  modiolus 
M,  plicatula 
M,  tulipa 
■M,  recta 

A.  atlantica 
P,  fiiuricata 
P.  seminuda 
P.  ephippium 
O.  virginica 
O,  frons 
O,  lurida 
P,  magellanicus 
jP.  irradians 
P,  dislocatus 
P.  islandicus 
P.  cequisideatus 
p.  hastatus 


405 


406 


MARINE  INVERTEBRATES 


Orders  Families  Genera 

EULAMELLIBRANCHIATA 

CARDiTiD^  Cardita 

ASTARTiD^  Astarte 

CYPRINID^  Arctica 


LUCINID^ 


Lucina 


,  Loripes 


Tellina 


Macofna 


DONACiD^      Donaoc 


TELLINID^ 


MACTRID^ 


VENERID^ 


Mactra 


L 

Venus 

Cytherea 

Dosinia 
Tivela 

Tapes 
Chione 
Saxidomiis 


Species 

c  C,  borealis 
^  C.  floridana 
\  A.  castanea 
( A,  undata 

A,  islandica 
I  L,  tigrina 
I  L,  floridana 
)  L,  pennsylvanica 
jL.  dentata 
I  L,  californica 
\  L.  nuttallii 

i.  edentula 

T.  radiata 

T,  altemata 

T,  bodegensis 

T,  tenera 

M,  secta 

M,  nasuta 

M,  baltica 

M,  proxima 
,M,  tenia 

D,  variabilis 

D,  californicus 
^M,  solidissima 

M.  siniilis 

M,  ovalis 
^M,  lateralis 

-K.  canaliculata 
i  F.  inercenaria 
j  Var.  tnortoni 
i  V.  cancellata 
5  C  (Callista)  gigantea 
I  C,( Callista)  fnactdata 
J  J),  discus 
( D,  elegans 

T.  crassatelloides 
^  T,  staminea 
(  T,  laciniata 
t  C.  succincta 
I  C,  fliictifraga 
(  C  similliiria 

S,  nuttallii 


PELECYPODS 

Families 

Genera 

Species 

PETRICOLID^ 

Petricola 

( P,  pholadiformis 
1 P,  carditoides 
1 C,  magnum 
1  C,  isocardia 
1  C.  Icevigatum 
\  C  serratum 
1  C,  mortoni 

CARDIID^ 

Cardiuni 

I  C.  substriatum 
J  C.  corbis 

j  C.  quadrigenarium 
1   C,  elatum 
\  C,  islandicum 
C.  pinnulatum 

MYIDiE 

Mya 

M,  arenaria 

[  Ensis 

E.  directus 

f  S,  viridis 
^  S.  sicarius 
L/Sf.  rosaceus 

SOLENID^ 

I  Solen 

\  Tagelus 

T,  gibbus 

GLYCIMERID^ 

Glycimeris 
r 

G.  generosa 
_P.  costata 

1  Pholas 

'  P,  truncata 

PHOLADID^    ■ 

I  P.  californica 

\Zirphcea 

Z.  crispata 

TEREDINID^ 

Teredo 

T.  navalis 

PANDORID^ 

JPandora 

JP.  trilineata 

407 


408 


MARINE   INVERTEBRATES 


ctr 


ccccd- 


V-  cxt.plp 


r.TTU 


l.inV.Jbijb 


Anatomy  of  a  pelecypod,  Anodonta  cygnea.  The  animal  with  most  of  the  left  mantle  lobe  removed. 
a,  excretory  opening;  a.  ad.,  anterior  adductor  muscle;  a.r.,  anterior  retractor  muscle;  aw.,  left 
auricle;  d.p.a.,  dorsal  pallial  aperture;  ex.  sph.,  exhalant  siphon;  ft.,  foot;  in.sph.,  inhalant 
siphon;  led.,  kidney;  I.  ext.  gl.,  left  external  gill;  I.  ext.plp.,  left  external  labial  palp  ;  I.  int.  gl.,  left 
internal  gill ;  I.  int. pip.,  left  internal  labial  palp  ;  I.  m.,  cut  edge  of  left  mantle  lobe;  mth.,  mouth; 
p.  ad.,  posterior  adductor  muscle;  pc,  pericardium;  p.r.,  posterior  retractor  muscle;  pre,  pro- 
tractor muscle  ;  ret.,  rectum  ;  r.  m.,  right  mantle  lobe ;  v,  ventricle ;  v.  m.,  visceral  mass. 


r.pa 
gap  rap    ^^j^^-'^^    rtui 


hi 


^   in.sph 


Anatomy  of  a  pelecypod,  Anodonta  cygnea.  Dissection  from  the  left  side,  a,  excretory  opening ; 
a.  ad.,  anterior  adductor  muscle;  a.ao.,  anterior  aorta;  a.v.ap.,  auiiculo-ventricular  aperture;  bl., 
urinary  bladder;  c.pl.  gn.,  cerebropleural  ganglion;  d.  d.,  duct  of  digestive  gland;  d.  gl.,  digestive 
gland;  d.p.a.,  dorsal  pallial  aperture ;  ex.  sph.,  exhalant  siphon;  ft.,  foot;  g.ap).,  genital  aperture. 
gon.,  gonad ;  gul.,  gullet ;  i.  l.j.,  interlamellar  junction  ;  in.  sph.,  inhalant  siphon  ;  iiit.,  intestine  ;  kd. 
kidney;  m,  mantle;  m<7i.,  mouth;  p.  oo.,  j)OSterior  aorta:  p.  ad.,  posterior  adductor  muscle;  pc, 
pericardium;  pd.  gm..,  pedal  ganglion;  r.  ap.,  renal  aperture ;  r.aii.,  right  auricle;  ret.,  rectum; 
r.p.  a.,  reno-pericardial  aperture  ;  St.,  stomach ;  ty.,  typhlosole ;  v.,  ventricle  ;  v.  gn.,  visceral  ganglion ; 
?«;.  t,  water-tubes. 


CLASS  PELECYPODA 

THIS  is  a  large  and  important  class  of  the  MoUusca,  compris- 
ing an  extensive  group  of  animals,  which  vary  widely  in 
structure.  Next  to  the  Gasteropoda,  it  is  the  largest  class  of  the 
phylum  in  number  of  genera  and  species.  The  name  indicates  a 
'^ hatchet-shaped"  foot,  but  in  many  cases  it  is  a  misnomer. 
Acephala,  meaning  "  without  a  head,"  is  also  employed  for  this 
class,  and  is,  perhaps,  a  better  term.  LamelUbranchiata,  referring 
to  the  type  of  gills  prevalent  throughout  the  division,  is  another 
name  often  used.  The  popular  name  ^'bivalves"  is  an  altogether 
correct  one,  for  all  the  animals  of  this  class  have  two  shells.  To 
the  Felecypoda  belong  the  oysters,  clams,  scallops,  mussels,  and, 
in  short,  all  the  bivalve  mollusks  (the  word  "  valve "  meaning 
"shell").  The  organization  of  a  pelecypod  is  entirely  similar  to 
that  of  a  gasteropod  or  a  chiton  in  its  fundamental  or  essential 
plan,  but  it  differs  widely  from  both  in  matters  of  detail.  If  the 
student  will  keep  in  mind  the  general  principles  of  gasteropod  or 
the  amphineuran  structure  when  he  dissects  his  first  pelecypod,  he 
will  quickly  see  that  the  latter  is  about  the  same  as  a  chiton  would 
be  were  it  folded  over  from  a  longitudinal  median  line  as  axis 
along  its  back,  so  that  the  opposite  mantle-edges  would  meet,  and 
its  various  shell-plates  would  unite  upon  either  side  into  a  single 
valve ;  or  it  is  very  like  a  gasteropod  made  symmetrical,  and  cov- 
ered upon  its  two  sides  by  separate  shells  instead  of  covered  over 
its  top  by  one  shell.  The  loss  of  head,  eyes,  and  tentacles,  the 
substitution  of  labial  palps,  the  extension  and  greater  develop- 
ment of  the  gills,  the  modification  of  the  foot  and  mantle,  and  the 
presence  of  certain  special  glands  in  the  Felecypoda  become  mere 
matters  of  anatomical  detail. 

409 


410  MARINE  INVERTEBRATES 

Any  large  clam  will  serve  for  dissection.  In  the  neighborhood 
of  New  York  the  edible  species  known  as  the  "  Little  Neck"  clam 
( Venus  mercenaria),  or  the  larger  Mactra  of  the  sandy  shores,  will 
answer  the  purpose  very  well.  In  Florida,  CalUsta,  Venus,  and  Car- 
dimn  are  all  available.  On  the  west  coast  the  large,  heavy  Tivela 
crassatelloides  is  probably  the  best  subject.  The  oyster  (Ostrea) 
is  a  degenerate  type ;  and  the  scallops  {Pecten)  and  the  mussels 
{Mytihis  and  Modiola)  have  certain  special  modifications  of  their 
organs  which  might  prove  confusing,  so  these  genera  are  not 
recommended  for  dissection  and  study  at  first. 

Boiling  is  apt  to  shrivel  and  distort  the  soft,  fleshy  animal  of 
the  bivalves,  and  it  is  far  better  to  examine  a  fresh  specimen. 
The  surest  way  of  opening  a  clam  without  injuring  the  animal  is 
to  break  one  of  the  shells  by  sharp  taps  of  a  hammer,  using  great 
care  not  to  lacerate  the  body  within  by  a  too  vigorous  assault. 
Pick  off  the  broken  pieces  after  having  separated  them  carefully 
with  a  knife  from  the  mantle  margin,  to  which  they  cling,  and 
after  having  cut  through  the  tough  adductor  muscles  as  close  to 
the  shell  as  possible.  The  subject  for  anatomical  study  is  then  pre- 
pared "  upon  the  half-shell." 

THE   MANTLE 

The  mantle  is  generally  very  thin,  often  a  fleshy  film  of  the 
finest  tissue,  and  adheres  to  the  inner  side  of  each  valve.  The 
outer  rim  of  the  mantle  is  thickened  and  free,  i.e.,  is  not  attached 
to  the  shell.  This  free  portion  is  capable  of  slight  extension 
beyond  the  margin  of  the  shell  when  the  valves  are  opened  and  the 
animal  is  off  guard.  In  many  genera  the  mantle  edge  is  highly 
ornate,  being  waved,  crenulated,  or  fluted,  or  is  beset  with  several 
rows  of  papillae,  and  is  often  richly  colored.  Mr.  Hickson,  a  nat- 
uralist, who  traveled  in  Celebes,  says  that  the  brilliant  coloring 
of  the  mantle  margins  of  moUusks  contributed  largely  to  the 
extraordinary  color-effects  upon  the  coral  reefs. 

It  will  be  seen  that  the  mantle  entirely  incloses  the  animal  at 
the  back  and  sides,  just  as  the  cover  of  a  book  incloses  the  pages 
or  printed  portion.  At  the  posterior  end  of  the  animal  there  is 
usually  a  point— or  perhaps  two  points— at  which  the  flaps  of 


PELECYPODS 


411 


1,  Solecurtus  strigillatus,  showing  pai'tly  united  siphons  covered  with  leathery  integument:  s.  af., 
incuiTent  siphon  :  s.  e/. ,  excurrent  siphon;  .S-S,  the  two  uniting.  2,  Cardhim  ednle,  showing  pai'tly 
united  siphons  with  papillaceous  orifices:  A,  excurrent ;  B,  incurrent  siphon;  F,  foot.  3,  Scrobicti- 
laria  piperata,  in  its  natural  position  in  the  sand,  showing  very  long  tubular  siphons ;  A,  excur- 
rent siphon  ;  B,  incurrent  siphon. 


the  mantle  lobes  unite  in  order  to  form  two  openings, 
openings  are  called  the  siphons. 


These 


SIPHONS 

In  some  cases  the  mantle  lobes  do  not  actually  unite  to  form 
regular  siphonal  openings,  but  in  life  the  free  mantle-edges  have 
a  way  of  adjusting  themselves  posteriorly  to  form  functional 
siphons  without  actually  coalescing.  Usually,  however,  the  man- 
tle flaps  not  only  unite  posteriorly  to  form  true  siphons,  but  are 
capable  at  that  point  of  varjdng  degrees  of  protrusion  from  the 
shell,  and  when  extended  the  siphons  appear  as  two  tubes.  In 
some  genera  these  siphonal  tubes  are  very  long ;  in  others  they 
are  fastened  together  and  surrounded  by  a  tough,  leathery  integu- 


412 


MARINE  INVERTEBRATES 


ment,  which,  like  the  siphons  proper,  is  only  an  extended  portion 
of  the  mantle-edge.  The  orifices  of  the  siphons  are  generally 
papillaceous.  These  two  siphons  (for  there  are  always  two  if 
there  are  any  at  all)  are  the  anal  or  excurrent  (upper)  and  the 
branchial  or  incurrent  siphon.  The  function  of  the  latter  is  to 
draw  in  the  pure  water  to  bathe  the  gills  and  to  furnish  food, 
while  the  office  of  the  former  is  to  eject  waste  materials  and  the 
water  which  has  already  passed  over  the  gills. 


Diagram  illustrating  the  various  degrees  of  iinion  of  the  mantle  lobes :  A,  mantle  completely 
open ;  B,  rudiments  of  siphons,  mantle  still  completely  open ;  C,  mantle  closed  at  one  point ;  D, 
mantle  closed  at  two  points,  with  complete  formation  of  siphonal  apertures ;  E,  development  of 
siphons,  ventral  closure  more  extended ;  F,  mantle  closed  at  three  points,  with  fourth  orifice ;  /, 
foot;  s.a.,  s.  b.,  anal  and  branchial  siphons;  1,  2,  3,  first,  second,  and  third  points  of  closure  of 
mantle ;  b.  o.,  byssal  aperture. 


MANTLE   FUSION 


Besides  the  points  of  juncture  where  the  mantle-edges  unite 
to  form  the  siphons,  the  coalescence  of  the  two  mantle  lobes  may 
be  extended,  and  they  may  become  further  united  and  fused  toge- 
ther at  other  points.  Indeed,  the  fusion  of  the  mantle-edges  may 
become  almost  complete ;  but  it  always  leaves  the  siphonal  open- 
ings and  a  third  opening  through  which  the  foot  may  be  extended. 
This  opening  for  the  foot  is  called  the  pedal  opening,  or  orifice. 
In  such  cases,  therefore,  the  mantle  becomes  much  like  a  bag  or 
sac.  The  degree  of  fusion  of  the  mantle-edges  appears  to  corre- 
spond closely  with  certain  changes  in  the  organization  of  the  ani- 
mal, and  this  feature  must  be  regarded  as  a  very  important 
character. 


PELECYPODS 


413 


The  figures  on  pages  411^  412,  and  413  show  the  degrees  of  man- 
tle fusion  in  various  groups  from  the  open  to  the  almost  wholly 
closed  types.  One  (A,  page  413)  gives  an  example  of  very  large 
siphons  united  together  and  protected  by  the  tough,  leathery  in- 
tegument. To  the  right  of  this  cut  may  be  seen  the  foot  project- 
ing from  the  pedal  opening  in  the  mantle.  Another  gives  the 
two  siphons  of  Cardium,  the  lower  or  branchial  one  being  the 
longer.  The  mantle-edges  below  are  fluted,  and  a  large  foot  pro- 
jects forward.  Another  shows  two  siphons  of  ScroUmlaria,  of  the 
free  and  greatly  extended  type.  Fig.  B  (page  413)  illustrates  the 
ventral  portion  of  a  pelecypod,  which  shows  very  well  the  most 
advanced  type  of  mantle  fusion. 
Besides  the  siphonal  openings 
at  the  end  of  the  long  projec- 
tion to  the  left,  the  only  other 
opening  is  the  very  small  orifice 
marked  "2,"  for  the  accommo- 
dation of  a  smaU,  insignificant 
foot.  In  the  other  figures  dif- 
ferent degrees  of  mantle  fusion 
are  indicated. 

Before  removing  the  mantle 
from  one  side  of  the  specimen 
to  be  examined,  note  the  two 

strong  muscles  which  are  at  either  end  of  the  body.  These  are 
the  anterior  and  posterior  adductor  muscles,  their  office  being  to 
hold  the  valves  tightly  shut.  They  are  of  great  strength,  as  any 
one  may  prove  to  his  satisfaction  by  attempting  to  open  a  clam. 
Through  a  long  series  of  forms  these  two  muscles  approach  each 
other  in  position,  and  in  the  scallops  and  the  oysters  there  is  but 
one  adductor  muscle,  occupying  a  central  position.  Morphologi- 
cally it  is  the  survival  of  the  posterior  adductor. 


A  :   1,  incurrent  siphon ;   2,  excurrent  siphon ; 
3,  foot.     B :   1,  siphons  ;  2,  pedal  opening. 


THE    BRANCHI^    OR   GILLS 


Removing  carefully  the  thin,  fleshy  mantle,  the  gills  are  ex- 
posed to  view— that  is,  of  course,  the  gills  of  that  side  of  4he 


414  MARINE  INVERTEBRATES 

animal,  for  there  are  two  sets,  one  upon  each  side  of  the  body, 
or  visceral  mass,  and  lying  between  the  body  proper  and  the 
mantle  folds.  Each  set  consists  of  two  plate-like  bodies  with  a 
texture  of  reticulated  or  basket  work  appearance.  Thus  there 
are  the  inner  and  outer  right  gills  and  the  inner  and  outer  left 
gills.  If  one  gill  is  removed  and  carefully  examined  it  will  itself 
probably  be  found  to  be  double,  consisting  of  many  filaments 
placed  side  by  side  and  then  doubled  back  like  a  row  of  hair- 
pins, the  filaments  being  united  by  interciliary  processes,  or  by 
vascular  channels  together  with  more  or  less  dense  connective 
tissue. 

The  modifications  of  the  pelecypod  gills  are  difficult  to  follow, 
but  the  principle  upon  which  they  perform  their  duties  is  the 
same  in  all  cases.  The  gill-filaments  are  all  connected  with  a 
long  vein,  and,  being  hollow,  admit  the  blood,  which  is  aerated  by 
close  contact  with  the  water  and  is  then  returned  to  another  vein 
in  immediate  connection  with  the  auricles  of  the  heart.  There  is 
another  function  accomplished  by  the  gills,  which  in  some  fami- 
lies seems  to  be  quite  as  important  as  their  respiratory  one, 
namely,  the  office  of  giving- lodgment  to  the  ova  while  in  process 
of  development  before  hatching.  At  certain  seasons  the  gills  of 
a  number  of  pelecypod  genera  become  literally  filled  with  eggs ; 
sometimes  this  curious  phenomenon  extends  to  the  mantle  itself, 
and  more  or  less  to  the  entire  surface  of  the  animal.  The  eggs 
are  first  regularly  ejected  from  the  genital  ducts  and  find  lodg- 
ment upon  the  body-surface,  but  usually  only  upon  the  gills, 
where  they  remain  as  in  a  brood-pouch  between  the  lamellae  of 
the  inner  and  outer  gills.  When  the  eggs  hatch,  the  free-swim- 
ming young  escape  from  the  mantle  cavity.  Probably  not  more 
than  one  individual  in  a  million  ever  reaches  maturity. 

The  figure  on  page  408  shows  the  mantle  removed,  exhibiting 
the  gills,  the  foot,  the  labial  palps,  and  the  pericardium,  inside  of 
which  is  the  heart.  Removing  the  gills,  we  find  exposed  the  body, 
or  visceral  mass,  which,  as  in  the  Gasteropoda,  is  thickened  below 
into  the  foot.  A  longitudinal  section  is  shown  on  page  408,  the 
visceral  mass  being  sliced  almost  through  the  middle ;  a  portion 
of  the  gills  of  the  farther  side  shows  below. 


PELECYPODS 


415 


THE   FOOT 


The  foot  undergoes  great  variation,  from  a  strong,  powerful 
organ  capable  of  forcing  its  way  through  heavy  gravelly  bottom 
or  burrowing  deeply  into 
the  sand  or  mud,  to  the 
merest  trace  of  a  pedal  or- 
gan. In  the  oyster  the 
foot  has  become  almost  en- 
tirely atrophied;  the  sta- 
tionary life  led  by  the  ani- 
mal renders  such  an  organ 
quite  nnnecessary.  Ex- 
cepting in  a  few  families, 
the  pelecypod  foot  is  well 

deVeiOpeCl.       in   a    number      MytHus  eduUs,  attached  by  its  byssus  (By)  to  a  piece  of 

of  genera  the  foot  contains  ^■''\^^  ^Z^''  ^'  ^-\"^™*  "^p^^"'  *^^  ^^ancwai  siphon 

o  being  below  it  and  not  closed. 

a  gland  for  the  secretion 

of  long  silk-like  or  horn-like  fibers,  which  are  collectively  called 
a  hyssiis.     The  use  of  a  byssus  is  for  attachment  to  any  object  to 

effect  a  temporary  or  per- 
manent lodgment.  The 
accompanying  cut  shows 
Mytilus  ediilis,  a  common 
east-coast  pelecypod,  at- 
tached by  its  byssus  to  a 
piece  of  wood.  Most  bi- 
valves having  a  strong  bys- 
sus exhibit  a  feeble  develop- 
ment of  the  foot ;  nearh^  all  bivalves,  however,  show  traces,  some- 
times only  in  the  embryo,  of  a  byssal  gland. 

The  visceral  mass  contains  the  liver,  the  exceedingly  large  gen- 
erative glands,  the  kidneys,  etc.,  and  through  all  this  soft  whitish  or 
reddish  mass  the  alimentary  canal  wanders  about  in  a  tortuous 
fashion,  finally  passing  through  the  pericardium  and  the  ventricle 
of  the  heart,  and  terminating  jnst  over  and  back  of  the  posterior 
adductor  muscle. 


Pecten  opercularis,  showing  the  ocelli,  or  eyes,  on  the 
two  edges  of  the  mantle. 


a» 


416  MARINE  INVERTEBRATES 

The  pelecypods  have  no  head  or  tentacles^  but  the  place  of  the 
latter  is'taken  by  two  pairs  of  triangular  flaps  upon  either  side  of 
the  mouth.  These  are  called  the  labial  palps,  and  they  no  doubt 
operate  by  means  of  their  ciliated  surface  to  keep  in  motion  the 
current  of  water  over  the  gills  and  to  the  mouth. 

As  a  rule,  pelecypods  have  no  eyes,  but  when  eyes  are  present 
they  are  situated  upon  the  edge  of  the  mantle.  The  eyes  are  not 
highly  developed  organs,  but  they  nevertheless  appear  to  be  very 
sensitive  to  light,  for  the  bivalves  which  are  so  endowed  will,  when 
kept  in  aquaria,  instantly  close  their  shells  when  the  shadow  of  a 
fish  passes  over  them. 

The  heart  lies  in  the  pericardium  and  is  situated  dorsally,  just 
in  front  of  the  posterior  adductor  muscle.  It  has  a  median  ven- 
tricle and  two  lateral  auricles,  each  connected  with  the  branchiae 
upon  its  respective  side.  It  seems  a  curious  economy  that  passes 
the  intestine  through  the  ventricle,  but  this  is  the  case  in  the 
great  majority  of  pelecypod  genera.  The  vascular  system  is  closed 
and  is  of  a  high  order.  It  is  probable  that  "  breathing  "  takes 
place  upon  the  inner  mantle  surfaces  as  well  as  in  the  gills  them- 
selves ;  for  these  surfaces  are  crowded  with  excessively  fine  and 
delicate  capillaries,  which  bring  the  blood  very  near  to  the  water. 
This  power  of  "  breathing  by  the  skin  "  is  quite  characteristic  of 
the  Mollusca  in  general. 

Having  once  familiarized  one's  self  with  the  more  prominent 
features  of  pelecypod  organization,  it  becomes  very  interesting 
to  examine  anatomically  every  new  form  that  is  captured.  Sur- 
prises are  always  in  store,  and  sometimes  the  peculiar  juxtaposi- 
tion and  relative  sizes  of  the  organs  are  a  trifle  confusing ;  but, 
upon  the  whole,  the  bivalve  organization  is  simple  and  lends 
itself  far  more  readily  than  does  that  of  the  gasteropods  to  satis- 
factory examination.  Some  of  the  more  striking  anatomical 
peculiarities  are  reserved  for  mention  in  the  notes  upon  the 
various  genera  and  species  common  upon  our  shores. 

THE   PELECYPOD   SHELL 

As  has  been  seen,  the  testaceous  covering  of  the  Pelecypoda 
consists  of  two  valves  or  shells  which  fit  more  or  less  closely  and 


PELECYPODS 


417 


firmly  together  and  are  placed  one  upon  either  side  of  the  animal. 
The  two  valves  are  always  held  together  tightly  along  a  dorsal 
margin  by  a  *4iinge  ligament,"  an  exceedingly  tough,  leathery 
substance,  and  they  are  usually  secured  the  more  firmly  by  a 
system  of  interlocking  teeth,  which  project  from  the  hinge.  The 
opening  and  shutting  of  the  valves  is  controlled  by  the  adductor 
muscles  of  the  animal,  by  the 
ligament  which  binds  the  valves 
together,  and  by  the  cartilage^  an 
elastic  pad  of  rubber-like  appear- 
ance which  is  lodged  just  with- 
in the  hinge,  and  is  compressed 
when  the  valves  are  closed  to- 
gether. Thus,  when  the  valves 
are  closed,  there  is  always  a  strain 
upon  the  adductor  to  overcome 
the  elastic  resistance  of  the  car- 

T      T  '^^^  interior    characteristics    of    a  pelecypod 

tllage.        When    a    pelecypod    dies  shell.  Left  valve  of  Fem(sc/mdia:  ^,  anterior,  B, 

T  j-i              n      _D  j^i           T  T        j_  posterior,    C,   dorsal,    D,   ventral   margin;    AB, 

and  the  pull  of  the  adductor  mUS-  length,    CD,   breadth  of    shell ;    a.  m,    anterior, 

cles  is  released,  the  valves  gape  ''■'\Tff''''''^T^::'T.^''l^^^^^ 

J  in    r       2y,  pallial  line;    p.  s.,  pallial  sinus;    J,  ligament; 

ODen  ^''•'  luniile;  m,  umbo;  c,  cardinal  teeth;   a.  I.,  an- 

^  ^  terior  lateral  tooth  ;  p.  I.,  posterior  lateral  tooth. 

The  summit  or  apex  of  the 
valve  is  called  the  nnibo,  or  l)eali.  It  is  usually  twisted  to  some 
extent,  and  in  certain  forms  develops  a  suggestive  spiral  figure. 
The  beaks  of  the  valves  are  the  points  where  the  shell-growth 
begins,  the  secretion  of  calcareous  matter  being  made  by  the  man- 
tle margin  and  deposited  about  the  edges  of  the  valves;  the 
growth  is  therefore  constantly  away  from  the  umbones. 

The  umbones  usually  point  forward.  In  many  species  they 
touch  each  other  over  the  hinge-margin  or  approximate  very 
closely;  in  other  species  the  hinge-margin  is  very  wide  and  the 
beaks  are  comparatively  far  apart.  The  hinge-margin,  lying  adja- 
cent to  the  umbones,  is  known  as  the  dorsal  margin  of  the  shell,  in 
contradistinction  to  the  ventral  margin^  opposite  the  umbones. 
The  anterior  margin  is  the  front  edge  and  the  posterior  margin  the 
hinder  edge  of  the  shells,  through  which  the  siphons  may  project. 

When  the  umbones  are  about  central  in  respect  to  the  posterior 

27 


418  MARINE   INVERTEBRATES 

and  anterior  margins,  the  shells  are  said  to  be  equilateral.  When 
the  two  valves  are  almost  exactly  alike  in  size  and  shape  they  are 
called  equivalve. 

In  many  forms  there  is  a  heart-shaped  space  upon  the  dorsal 
margin  of  the  closed  valves  forward  of  the  nmbones,  called  the 
luniile.  Similarly  placed  back  of  the  nmbones  is  sometimes  a 
more  or  less  clearly  defined  space  called  the  escutcheon.  The  outer 
surface  of  bivalve  shells  admits  of  infinite  variety  of  sculpturing 
and  ornamentation,  ranging  from  a  perfectly  smooth  to  a  heavily 
ribbed,  nodose,  spinous,  or  deeply  decussated  surface.  The  color- 
markings  are  often  brilliant  and  eccentric. 

The  right  and  left  valves  may  be  distinguished  by  remember- 
ing that  the  siphons  are  always  posterior,  and  that  the  umbones 
usually  point  forward. 

The  hinge  of  bivalve  shells  undergoes  many  variations  in  the 
different  genera.  The  simplest  type  is  a  smooth  edentate  surface 
where  the  two  valves  meet  and  are  held  together  only  by  the 
strong  ligament.  General^,  however,  there  is  a  system  of  inter- 
locking teeth,  those  in  the  center  of  the  hinge  being  the  cardinals 
and  those  upon  either  side  the  laterals.  In  some  forms  there  are 
rows  of  fine  comb-like  teeth  along  the  hinge-margin,  with  no  dis- 
tinction between  cardinals  and  laterals. 

The  object  of  these  hinge-teeth  is  at  once  obvious,  for  they 
give  a  rigidity  and  increased  strength  to  the  entire  mechanism, 
especially  when  closed.  There  is  occasionally  a  saucer-shaped 
plate  or  platform  just  under  the  cardinal  teeth  and  within  the 
shell,  called  the  fossette.  Upon  this  rests  the  internal  elastic 
cartilage. 

Upon  the  smooth  interior  surfaces  of  the  valves  are  always  cer- 
tain markings,  which  correspond  to  anatomical  features  of  the 
animal  and  are  consequently  of  considerable  importance  in  the 
determination  of  the  systematic  position  of  the  specimen.  First, 
the  well-marked  impressions  left  by  the  adductor  muscles  will  be 
noted ;  then  a  more  or  less  distinct  line  which,  describing  roughly 
a  circle,  connects  the  two  muscle  scars.  This  line  represents  the 
points  at  which  the  mantle  became  detached  from  the  shell.  In 
other  words,  all  the  space  within  this  pallial  line  (barring  the 


PELECYPODS  419 

muscle  scars)  was,  in  life,  covered  by  the  mantle,  which  adhered 
tightly  to  it.  The  space  between  this  pallial  line  and  the  outer 
edge  of  the  valve  was  occupied  in  life  by  the  free  portion  of  the 
mantle.  Frequently  a  depression  in  the  pallial  line  toward  the 
center  of  the  valve  is  seen  in  the  posterior  end.  This  is  called 
the  pallial  sinus,  and  marks  the  space  occupied  by  the  siphons. 
The  pallial  sinus  is  absent,  moderate,  or  deep,  according  as  the 
animal  possessed  no  siphons,  or  small  or  large  ones. 

The  length  of  bivalve  shells  is  measured  from  their  anterior  to 
their  posterior  ends,  while  the  height  indicates  the  greatest  diam- 
eter between  the  umbones  and  the  ventral  margin. 

The  greatest  possible  degree  of  variation  exists  in  the  structure 
of  the  pelecypod  shell.  Every  degree  of  thickness  from  the  most 
fragile,  tissue-like  structure  to  the  very  heavy  and  ponderous 
tests  of  some  of  the  Yeneridce  is  to  be  found.  There  is  also  a 
range  in  size  from  the  very  minute  SpJieria  to  the  giant  Tridacna 
of  Eastern  seas,  which  weighs  several  hundred  pounds.  As  in  the 
Gasteropoda,  there  is  fortunately  a  very  close  parallelism  between 
shell  and  anatomical  variations.  One  very  quickly  learns  to 
place  a  bivalve  in  its  systematic  position  by  a  mere  glance  at  the 
shell  alone.  While  the  higher  classification  into  orders,  sub- 
orders, etc.,  is  based  upon  anatomical  features,  the  genera  often 
and  the  species  always  are  founded  upon  conchological  or  shell 
characters. 

The  PeJecypoda  offer  one  of  the  most  interesting  fields  for 
investigation  and  study  among  the  invertebrates.  Although  by 
no  means  neglected,  they  have  not  received  as  much  attention  on 
the  part  of  biologists  as  has  been  given  to  other  phyla,  or  indeed 
to  the  other  classes  of  this  same  phylum. 

CLASSIFICATION   OF   THE   PELECYFODA 

Nearly  every  systematic  writer  upon  the  mollusks  has  attempted 
to  give  a  good  classification  of  the  bivalves,  yet  none  of  the  results 
is  wholly  satisfactory.  The  scheme  now  generally  adopted  is 
one  based  upon  modifications  of  the  gills,  or  branchise,  and  has 
practically  replaced  all  the  older  classifications,  which  depended 


420 


MARINE   INVERTEBRATES 


upon  the  presence  or  absence  of  siphons,  the  degree  of  mantle 
fusion,  the  arrangement  of  teeth  upon  the  hinge,  the  number  of 
adductor  muscles,  etc.  The  idea  of  arrangement  according  to 
gill-structure  is  substantially  this:  the  development  of  the  gill 
from  the  simplest  and  most  rudimentary  type  through  successive 
stages  to  a  higher,  more  complex,  and  presumably  more  effi- 
cient type,  marks  the  natural  progress  or  development  of  the 
pelecypod  animal  itself.  By  adopting  the  gill  as  a  guide  one 
follows,  therefore,  a  natural  method.  Upon  the  other  hand,  the 
presence  or  absence  of  siphons,  the  shape  of  the  foot,  the  number 
of  adductor  muscles,  all  depend  merely  upon  the  acquired  habits 
of  the  animal,  these  particular  features  being  subject  to  modifica- 
tion according  to  environment  and  changed  conditions. 

The  five  orders  of  the  Felecypoda  are:  ProtohrancJiiata,  Fili- 
hnmchiata,  FseudoIameUihranchiata,  EulamelUhranchiata,  Septi- 
hranchiata. 


m 


Structure  of  the  branchias  or  gills  of  pelecypods,  seen  diagrammatically  in  section : 
A,  Protobranchiata ;  B,  FilihrancMata ;  C,  Eulamellibranchiata ;  D,  Septihranchiata ; 
e,e,  external  row  of  filaments;  i,i,  internal  row  of  filaments;  e',  external  row  or 
plate  folded  back ;  i\  internal  row  folded  back ;  /,  foot ;  m,  mantle ;  s,  septum ; 
V,  visceral  mass. 


The  first  includes  the  simpler  type  of  gill  as  represented  in  the 
accompanying  figure  (A).  Its  filaments  are  short  and  not  reflected. 
The  second,  represented  in  Fig.  B,  has  the  filaments  long,  reflected, 
and  connected  (each  filament  to  its  adjacent  ones)  by  means  of  sur- 
face cilia.  The  third  type  of  gill  resembles  the  last  except  that  the 
ends  of  the  filaments  of  the  outer  gill  are  attached  to  the  mantle, 
and  the  ends  of  the  filaments  of  the  inner  gill  are  attached  to  the 
foot  or  visceral  mass.     The  fourth  type  of  gill  is  far  more  highly 


PELECYPODS  421 

developed.  The  adjacent  filaments  are  connected,  not  by  cilia, 
but  by  vascular  channels^  and  the  depending  and  recurved  por- 
tions of  each  filament  are  also  connected  in  a  manner  presumed 
to  admit  of  the  passage  of  blood.  This  gives  to  the  organ  the 
appearance  of  basketwork  or  network.  The  ends  of  the  filaments 
are  attached  to  the  mantle  and  to  the  visceral  mass,  as  in  the 
last  order,  forming  cavities  or  chambers  above  (see  Fig.  C).  This 
order  includes  the  great  majority  of  the  Felecijpoda. 

The  fifth,  and  last  order  is  confined  to  but  two  rather  obscure 
families,  in  which  the  gill-development  is  carried  to  the  point  of 
substitution  of  muscular  partitions  which  form  a  separate  cham- 
ber connected  with  the  mantle  cavity  by  a  narrow  slit,  the  surface 
of  the  chamber  having  respiratory  functions  (Fig.  D). 

The  collector  of  living  marine  objects  who  has  become  fasci- 
nated by  their  beauty  and  who  derives  pleasure  from  examining 
the  greater  beauty  of  their  structures  will  find  a  rich  field  for 
research  in  the  pelecypod  gills.  But  unless  he  has  time  at  his 
disposal  and  some  skill  with  a  microscope,  he  would  do  well  not 
to  venture  too  far  into  this  alluring  but  difficult  and  vexatious 
subject. 

Our  coastal  waters  are  fairly  rich  in  bivalves,  but  the  most 
strikingly  handsome  species  of  this  class— and  there  are  many  of 
them— are  inhabitants  of  warmer  seas.  Of  the  great  number 
of  bivalves  to  be  found  upon  our  own  shores  we  can  only  men- 
tion briefly  some  of  the  commonest  species. 


ORDER    PROTOBRANCHIATA 

Fainiily  NUCULIDa: 

In  this  family  the  gills  are  of  the  simplest  and  most  primitive 
type.  The  mantle-edges  are  entirely  open  along  the  ventral 
margin,  but  they  are  united  posteriorly  in  some  of  the  N^uciiJidm 
to  form  two  short  siphons.  The  palps  are  exceedingly  large.  The 
foot  is  also  large,  and  by  its  disk-like  surface  is  adapted  to  creep- 
ing, much  as  is  a  gasteropod  foot ;  its  edges  are  often  crenulated  or 
scalloped,  and  there  is  no  trace  of  a  byssus.     The  shells  are  equi- 


422 


MARINE  INVERTEBRATES 


valve,  and  tlieir  most  prominent  feature  is  the  hinge,  which  is 
beset  with  sharp,  comb-like  teeth  in  two  straight  rows,  one  upon 
each  side  of  a  central  pit,  a  space  reserved  for  the  ligament. 


Genus  Nucula 

N,  proxima*  The  commonest  of  several  species  of  the  genus  found 
along  the  New  England  coast.  It  is  oblique,  with  a  hght-olive  epider- 
mis, nacreous  interior,  and  finely  creuulated  margins.  Its  length 
is  about  one  quarter  of  an  inch.  The  animal  has  no  siphons. 
It  lives  in  either  muddy  or  pebbly  stations  near  the  shore,  and 
probably  exists  in  countless  thousands  in  all  the  bays  and  har- 
bors of  the  New  England  coast. 


Genus  Leda 

i.  tenuisulcata.  This  species  has  a  longer  shell 
than  the  preceding;  it  is  more  produced  behind, 
and  is  narrowed  into  a  blunt,  slightly  gaping  point. 
The  epidermis  is  hght  greenish,  and  the  shell  has 
a  pearly  luster  within.  The  outer  surface  of  the 
shell  is  concentrically  grooved ;  the  beaks  ^  are 
smooth.  The  foot  is  disk-shaped,  and  the  animal 
is  provided  with  small  siphons.  The  length  of 
this  shell  is  about  one  inch.  Its  station  is  the  muddy 
bottom  in  shoal  water  on  the  New  England  coast. 


Leda  tenuisulcata. 


Genus  Yoldia 

Y,  Umatula,  This  species  has  the  same  sort  of  toothed  hinge  exhib- 
ited in  the  two  preceding  species,  but  the  shell  is  considerably  larger 

(two  inches),  with  a  smooth 
greenish  glazed  epidermis. 
The  beaks  are  nearly  central. 
The  interior  of  the  shell  is 
light  bluish  and  pearly.  The 
animal  has  two  slender,  short, 
united  siphons  and  a  disk- 
shaped  foot  with  simple  mar- 
gins. This  species  can  make 
excellent  use  of  its  foot,  for 
it  crawls  with  rapidity,  and 
also  can  execute  leaps  in  an  astonishing  manner.  Found  in  muddy 
stations  in  shoal  water  on  the  New  England  coast. 

Y,  thraciceformis,  A  much  larger  species,  found  on  the  New  England 
coast.  It  may  be  distinguished  by  a  rib-like  wave  extending  obhquely 
from  the  umbones  to  the  ventral  margin  of  the  sheU.     It  measures  over 


Yoldia  Umatula. 


PELECYPODS 


423 


two  and  a  half  inches  in  length  and  one  and  a  half  inches  in  height, 
and  is  dark  olive- green.  The  foot  is  like  that  of  Y.  Umatula.  The 
labial  palps  are  exceedingly  large. 

Y,  sapotilla.  The  shell  is 
ovate,  prolonged  on  one  side, 
thin,  fragile,  translucent,  and 
covered  with  a  thin,  glossy  epi- 
dermis, greenish  in  color.  The 
anterior  half  is  semi- oval,  the 
posterior  portion  narrowed  and 
compressed  ;  within  it  is  pearly- 
white,  with  a  triangular  cartilage 
cavity,  and 
sixteen  to  eigh- 
teen     pointed 

teetn    on     eacn  YolcUa  thracuejormis. 

Yoidi     imfua        ^i^c.  In  length 

sapo  I  a.       .^  ^^  Httle  less  than  an  inch.    Found  from  Long  Island 
Sound  northward. 

Family  solenomyid^ 
Genus  Solenowiya 

Two  species  of  this  genus,  v^hich  are  greatly  prized  by  collectors 
on  account  of  the  extraordinary  development  of  the  epidermis  of 
the  shell,  occur  in  New  England  waters.  The  strong  corneous 
periostracum  of  a  deep  chestnut-color  projects  considerably  be- 
yond the  margins  of  the  valves  j  the  shells  are  exceedingly  thin 
and  fragile,  and  are  marked  with  radiating 
lines.  The  two  species  are  easily  distinguished 
by  their  difference  in  size.  S,  velum  is  about 
one  inch  long  and  one  half  of  an  inch  high. 
S,  borealis,  of  arctic  range,  is  quite  twice  that 
size.  Their  anatomy  is  similar  in  essentials  to  that  of  Yoldia. 
These  species  live  near  shore  in  sandy  bottoms,  and  are  occa- 
sionally found  upon  the  beach  between  tides.  Chelsea  Beach, 
just  north  of  Boston,  is  an  often-quoted  locality. 

ORDER  FILIBRANCHIATA 

There  are  several  families  of  this  order  which  are  well  repre- 
sented in  both  the  Atlantic  and  the  Pacific  waters  of  the  United 
States.  The  characteristic  feature  of  this  group  of  bivalves  is  the 
filamentous  gill,  that  is,  a  gill  with  the  filaments  long,  doubled 
back,  and  united  to  each  other  only  by  ciliary  junctures.     These 


Solenomya  velum. 


424 


MARINE  INVERTEBRATES 


junctures  are  so  sUght  that  they  break  readily  when  a  specimen 
of  a  gill  is  handled,  leaving  the  filaments  free.  The  presence  of  a 
byssal  gland  in  the  foot,  and  often  a  well-developed  byssus,  is 
another  characteristic  of  this  order. 

Family  anomiidje 

Genus  Anomia 

This  is  a  family  of  peculiar  and  highly  specialized  forms. 
Anomia  has  an  irregularly  rounded  shell,  with  one  convex  and 
one  flat  or  concave  valve.  There  is  no  regular  hinge  or  well- 
defined  hinge-margin,  but  a  raised  f  ossette,  or  cartilage  plate,  occu- 
pies a  position  at  the  top  of  the  valves.  In  the  flat  valve  there 
is  a  large  oblong  hole  just  under  the  apex,  through  which  projects  a 
calcified  byssus,  by  means  of  which  the  animal  secures  itseK  to 
oysters,  dead  shells,  stones,  or  any  solid  object.  The  anomias,  w^hich 
have  become  stationary  in  habit,  have  practically  lost  their  foot. 
The  gills  are  very  large  and  curved,  while  all  the  organs  seem  to 
be  abnormally  placed  on  account  of  the  huge  byssus  and  byssal 
muscle.  For  the  byssus  to  pass,  as  it  does,  through  a  specially 
prepared  hole  in  one  of  the  valves  is  an  extraordinary  departure 
from  the  conventional  types  of  byssiferous  species.  The  heart  is 
not  traversed  by  the  intestine.  Altogether,  then,  Anofnia  is  a  very 
curious  genus. 

A,  simplex.  The  commoner  large  form  of  New  England.  It  varies 
from  one  to  three  inches  in  diameter,  is  exceedingly  irregular  in  shape, 

and  its  surface  is  var- 
iously undulated  and 
plaited  in  accordance  with 
the  surface  of  the  ob- 
ject to  which  it  is  at- 
tached. Thousands  of 
these  valves,  disjointed 
and  separated,  are  cast 
upon  the  beaches  all  along 
our  Atlantic  coast.  They 
are  light  green  to  sal- 
mon- or  copper-color, 
generally  fragile  and 
scaly,  and  have  a  pecu- 
liarly dulled   (as  though 

Aiiomia  simplex,  side  view.   Anomia  simplex,  from  below.  greaseo.)  Uacre. 


PELECYPODS 


425 


Anomia  aculeata,  from 
Anomia  aculeata,  from 


above, 
below. 

east- 


A,  aculeata  is  much  smaller  than  the  last  species, 
and  the  surface  of  the  convex  valve  is  roughened 
by  prickly  scales.  The  smaller  valve  is  very  thin, 
with  an  almost  circular  aperture  for  the  byssus. 
Its  diameter  is  about  half  an  inch.  Found  at- 
tached to  stones,  etc.,  about  the  holdfasts  of  Fucus. 

A,  lainpe,  a  California  species  ranging  more 
to  the  south,  is  small  (half  an  inch),  and  greatly  resembles  the 
coast  A.  aculeata,  save  as  regards  the  smooth  surface  of  the  former. 

Genus  Placunanomia 

P.  macrocMsma.  This  species  occurs  on  the  Calif  ornian  coast.  It  has 
the  same  sort  of  calcified  byssus  as  Anomia,  and  also  the  hole  to  accom- 
modate it  in  the  smaller  valve.  The  scar  formed  by  the  muscle  which 
controls  the  byssus  is  curiously  rayed  in  this  genus.  The  normal  shape 
of  the  shell  is  circular ;  it  is  pearly  within,  and  of  a  greenish  tinge  with- 
out.    Two  to  four  inches  in  diameter.     (Plate  LXXVIII.) 

Family  aecid^ 

Genus  Area 

The  Arcidce  may  always  be  distinguished  by  the  long  row  of 
comb-like  teeth  upon  the  hinge,  the  total  want  of  siphons  (a  fact 
which  may  be  discovered  in  the  shell  alone  by  its  lack  of  a  pallial 
sinus),  and  the  solid  trapezoidal  or  round  shell,  with  its  tendency  to 
strong  ribs  radiating  from  the  umbones.  The  periostracum,  or 
epidermis,  is  heavy  and  often  velvety  or  even  hairy.  The  animal 
of  Area  has  the  gills  placed  in  an  oblique  position ;  the  foot  is 
large  and  strongly  developed.  No  trace  of  mantle  fusion  exists. 
The  mantle-edges  bear  a  row  of  composite  eyes.  The  gill-fila- 
ments are  entirely  free,  there  being  even  no  ciliary  junctions. 

A,  pexata.  An  exceedingly 
common  species  in  Long  Island 
Sound  and  on  the  coast  of  New 
Jersey.  The  shell  is  oblong,  with 
prominent  beaks  directed  forward. 
The  hinge-teeth  are  an-anged  in 
a  row  posterior  to  the  beaks,  while 
just  under  the  beaks  are  a  num- 
ber of  irregular  cartilage -pits. 
About  thirty-two  to  thirty-six  ra- 
diating ribs  ornament  the  shell. 
The  inner  margins  of  the  shell  are 
yr^Y^'^^^r^    '  rather  deeply  scalloped  j  the  epi- 

Arca  pexata.  dermis  is  tMck,  shaggy,  and  dark 


426  MARINE  INVERTEBRATES 

brown.  Length  two  to  two  and  a  quarter  inches ;  height  two  inches. 
A.  pexata  is  one  of  the  few  pelecypods  which  have  red  blood,  a  fact 
which  accounts  for  its  popular  name  of  '*  bloody  clam." 

A,  ponderosa.  The  most  prominent  Area  upon  our  Atlantic  coast, 
especially  south  of  Virginia.  The  beaks  of  this  shell  are  very  promi- 
nent, and  do  not  approach  each  other  very  closely  on  account  of  the 
wide  dorsal  margin  of  the  shells,  the  large  space  between  the  beaks 
being  occupied  by  an  external  ligament.  The  hinge- teeth  are  smaller 
in  the  middle.  There  are  from  twenty-five  to  twenty-eight  ribs;  the 
ventral  margin  of  the  valves  is  somewhat  contracted  in  the  middle. 
Length  two  and  a  half  inches ;  height  two  inches.  Very  heavy  and 
solid.  This  exceedingly  common  species  is  often  cast  upon  the  beaches 
south  of  Hatteras  in  numbers  beyond  computation.  In  life  it  is  covered 
with  a  heavy,  coarse,  velvety  epidermis,  almost  jet-black  in  color. 
(Plate  LXXVin.) 

A.noce.  The  well-known  '^Noah's-ark"  shell,  a  common  species 
along  the  shores  of  the  Southeastern  States.  It  also  occurs  in  the 
Mediterranean.  Unlike  most  areas,  it  spins  a  byssus,  by  means  of  which 
it  attaches  itself  to  the  under  surfaces  of  stones  at  low  water.  The 
hinge-margin  is  perfectly  straight  and  regularly  toothed.  The  beaks 
are  high  and  are  situated  very  far  forward.  The  dorsal  margin  of  the 
valves  is  strikingly  large,  and  is  marked  by  lattice-hke  grooves  j  it  forms 
a  concave  surface  over  an  inch  in  width  between  the  umbones.  The 
shell  is  strongly  ribbed  without.  The  ventral  margin  of  the  valves  is 
sinuous  and  gapes  slightly  at  a  central  point  for  the  accommodation  of 
the  byssus.     (Plate  LXXVIII.) 


Family  mytilid^ 
Genera  Mytilus,  Modiola 

The  Mytilidm  are  a  large  family,  including  the  mussels,  so  com- 
monly found  between  tides  upon  all  shores.  The  two  ordinary 
genera  Mytilus  and  Modiola^  which  often  occur  associated  to- 
gether upon  our  eastern  coast,  may  readily  be  distinguished  one 
from  the  other  by  the  position  of  their  beaks.  In  the  former 
genus  the  beak  is  terminal,  that  is,  it  is  situated  at  the  very  tip- 
end  of  the  shell;  in  the  latter  genus  it  is  not  quite  terminal. 
Aside  from  this  simple  feature,  the  genera  are  practically  the 
same,  the  animals  being  identical.  Mytilus  and  Modiola,  com- 
monly known  as  mussels,  have  acquired  the  stationary  habit  and 
are  provided  with  a  relatively  small  foot  (in  some  species  amount- 
ing to  no  more  than  a  mere  tubercle) ;  but  in  place  of  a  useful 
foot  is  a  well-developed  byssogenous  gland,  which  secretes  an  ex- 


PLATE   LXXVIII. 


Placunanomia  macrochisma. 
Area  nose 


Area  ponderosa. 
Mytilus  hamatus. 


PELECYPODS  427 

ceedingly  tough,  fibrous  byssiis.  By  means  of  this  the  animal  may 
not  only  attach  itself  firmly  to  any  sort  of  object,  but  may  actually 
move  about.  Fibers  of  the  byssus  are  thrown  out,  and,  as  though 
possessed  of  life,  they  seize  upon  objects  in  the  direction  in  which 


JMytilus  eclulis,  typical  form. 

Mytilus  desires  to  move,  and  by  contraction  of  the  muscles  which 
control  the  byssus  the  animal  is  drawn  forward,  t£e  operation 
being  then  repeated.  It  must  be  a  very  tedious  method  of  travel. 
However,  the  Mytilidce  are  not  restless  creatures.  They  p«iss 
their  lives  content  to  remain  firmly  fixed  to  some  object,  and 
their  movements,  if  any,  are  within  a  very  narrow  circle.  The 
animal  has  very  long  gills  of  the  usual  filamentous  type.  The 
mantle  fuses  at  one  point  to  form  an  anal  siphon,  the  lower  or 
branchial  one  being,  therefore,  functional.  The  palps  are  large. 
One  curious  feature  of  this  group  is  the  enormous  extent  of  the 
genital  glands,  which  actually  appear  to  pervade  the  entire  struc- 
ture of  the  animal,  gills,  mantle,  foot,  and  all.  At  times  the 
whole  being  is  a  veritable  receptacle  for  myriads  of  tiny  yellowish 
eggs. 

The  Mytilidce  are  of  universal  distribution,  and  are  for  the 
most  part  of  littoral  or  shallow-water  range.  Some  species 
are  esteemed  as  an  article  of  food,  notably  Mytilus  edulis. 

Mussel-culture  has  been  profitably  carried  on  in  France  for  a 
long  time,  but  the  genus  has  not  been  utilized  to  any  extent  a^ 
food  in  this  country. 


428 


MARINE  INVERTEBRATES 


Mytilus  edulis,  rayed-color  variety. 


Mytilus  edulis  is  exceedingly  abundant  along  the  New  England 
coast.     It  lives  in   colonies,  often  between  tides,  in  pebbly  stations 

among  large  rocks.  It  is  always 
so  fastened  by  its  byssus  that  the 
beaks  of  the  valves  point  down- 
ward, and  the  ventral  margin  pro- 
jects above  the  sand  or  mud. 
The  color  of  the  epidermis  in  the 
adult  form  is  black  or  a  deep  blue- 
black  5  the  shell  proper  is  violet. 
Hinge-teeth  are  wanting.  Length 
two  and  a  half  inches.  A  va,riety 
of  this  species,  M,  pellucidus, 
is  often  f otmd  associated  with  the  typical  form.  It  is  brightly  rayed  in 
green  and  yellow.  M.  edulis  occurs  in  Europe,  where  it  is  quite  exten- 
sively used  as  food.  It  also  occurs  (by  importation)  in  San  Francisco 
Bay. 

M.  hamatus  has  a  more  southern  range  than  has  M.  edulis,  and  is 
found  from  the  Chesapeake  southward.  Its  shell  is  considerably  twisted 
just  below  the  umbonal  region,  while  its  whole  surface  is  densely  striated. 
Its  color  is  dark  fuscous.  Length  one  to  two  inches.  It  is  found  in 
great  numbers  attached  to  oysters  by  its  byssus.  In  Florida  it  is  very 
common.     (Plate  LXXVIII.) 

M,  califomimis.  A  common  west-coast  species,  which  finds  its  sta- 
tion among  rocks  exposed  to  the  surf.  It  is  about  the  same  size  as  M. 
edulis,  but  has  a  lighter  brownish  glossy  epidermis  and  several  con- 
spicuous, well-rounded,  radiating  ribs.     The  animal  is  orange-colored. 

Modiola  ntodioliis.  After  violent  storms  upon  the  New  England 
coast,  when  a  large  Laminaria  is  wrenched  from  its  rocky  bed  and 
washed  ashore,  its  roots  will,  in  many  cases,  be  found  clinging  to  this 
large  mussel.  The  thick  glossy  epidermis  of  deep  chestnut-color  folds 
over  the  margin  of  the  valves,  and  the  outer  surface,  especially  near  the 
ventral  margin,  is  covered  with  a  tough  hairy  growth.  Length  four  to 
five  inches.  The  animal  is  orange-red.  The  great  size  and  swelling  full- 
ness of  this  species  at  once  distinguish  it  from  all  others  upon  our  coast. 
It  is  not  a  shallow-water  form, 
but  is  extremely  common  upon 
all  beaches  north  of  Hatteras. 
It  also  occurs  in  Alaskan 
waters  to  Puget 
Sound,  where  it 
is  known  as  the 
"  great  horse- 
mussel."  Some- 
times these  large 
modiolas  may  be 
found  in  rocky 
tide-pools  which 
are  washed  by  the  surf  at  high 
tide.  They  hide  far  back  in 
the  crevices  of    boulders,   and  Modwu  modiolus. 


PELECYPODS 


429 


are  not  easily  detected.     They  are  not  uncommon  in  such  stations  at 
Mount  Desert,  Maine. 

M,  plicatula.  This  species  of  Modiola  ranges  from  Canada  to  Hat- 
teras,  and  inhabits  the  tidal  waters  of  streams,  sheltered  muddy  reaches 
among  reeds,  and  tidal  flats.     It  is  a  dingy -looking  shell,  ornamented  with 


Modiola  plicatula,  typical  form. 

numerous  radiating  ribs,  which  are  very  fine  upon  the  anterior  portion 
of  the  shell.  The  epidermis  is  thin  and  of  a  dirty  yellowish -green  color. 
Within  it  is  silvery- white.  In  the  ventral  margin  there  is  an  opening  for 
the  accommodation  of  a  byssus.  Length  about  three  inches  in  New 
England ;  slightly  larger  at  Norfolk.  There  is  probably  no  muddy  reach 
of  land  that  is  exposed  at  low  tide  from  Maine  to  the  Carolinas  that  is  not 
inhabited  by  M.  plicatula. 

M.  tulipa.  This  is  the  "  show  shell "  of  the  genus  Modiola  in  American 
waters.  It  belongs  to  the  Southern  fauna,  and,  hke  the  others  of  its 
genus,  it  moors  itself  to 
wood  or  other  solid  ob- 
jects by  means  of  its 
byssus.  It  is  of  about 
the  same  size  as  the  last 
species,  but  is  perfectly 
smooth  and  of  a  bright- 
yellowish  color,  with 
dark  rays  over  the  cen- 
tral portion. 

M,  recta,  A  species 
of  Modiola  fairly  abun- 
dant on  the  Pacific  coast 
fromVancouverto  south- 
ern California.  It  has  a 
long,  narrow  shell  with  a  dark-brown  glossy  epidermis ;  hghter  pos- 
teriorly, and  with  a  short  hairy  growth.  The  interior  is  white.  Length 
three  to  four  inches. 

ORDER   PSEUDOLAMELLIBRANCHIATA 

This  third  order  of  PeJecypoda  is  made  up  of  a  number  of  fami- 
lies in  which  the  gills  are  filamentous,  but  in  which  the  filaments 


Modiola  nigra. 


430  MARINE   INVERTEBRATES 

have  become  united  at  their  ends  to  the  mantle  (on  the  outer  gills) 
and  to  the  body-mass  (on  the  inner  gills).  Here  also  the  first  traces 
of  the  higher  type  of  gill  found  in  the  next  order  appear ;  that  is,  a 
gill  in  which  the  filaments  are  counected  by  vascular  channels  in- 
stead of  by  cilia.  This  order  therefore  is  presumed  to  connect 
the  true  filamentous  type  of  gill  with  the  fully  developed  lamellar 
type.  As  the  filaments  do  not  always  fuse  with,  the  mantle  or 
foot,  the  description  of  the  pseudolamellibranch  gill  becomes 
somewhat  vague,  and  there  is  some  room  for  doubt  whether  this 
order  should  exist  at  all. 

Most  of  the  genera  placed  in  it  are  monomyarian ;  that  is,  they 
have  but  one  adductor  muscle,  or  if  two,  the  anterior  one  is  very 
small  and  unimportant.  The  mantle-edges  are  entirely  open, 
there  being  no  regularly  formed  siphons.  As  a  rule,  the  foot  is 
exceedingly  small  or  quite  aborted. 

Family  AvicuLrD.ffi: 

In  this  family  there  is  an  exception  to  the  rule  just  stated :  the 
foot  is  long.  There  is  a  byssus,  and  the  gills  (by  their  outer 
ascending  filaments)  are  concrescent  with  the  mantle. 

The  interior  of  all  the  Aviculidm  is  of  a  highly  polished  nacre, 
and  some  of  the  larger  species  have  been  extensively  collected  for 
mother-of-pearl.  To  the  Aviculidm  belong  the  pearl-oysters 
{Meleagrina  margaritifera). 

A  delightful  air  of  romance  and  adventure  surrounds  the 
pearl-fisheries,  about  which  much  has  been  written.  The  pearl  is  an 
abnormal  product  formed  by  the  deposition  of  nacre  around  some 
foreign  object,  such  as  a  grain  of  sand,  or— usually,  it  is  said — 
an  egg  which  has  failed  to  develop  properly.  They  are  seldom 
found  in  individuals  having  favorable  conditions  of  growth,  but 
those  which  are  greatly  crowded  together  and  covered  with  va- 
rious parasites  and  growths  are  most  productive  of  them.  The 
pearl  is  the  same  in  substance  as  the  nacreous  shell  of  the  pearl- 
oyster,  and  its  iridescence  is  due  to  the  fine  strige  of  the  undulat- 
ing layers  of  which  it  is  composed.  The  pearl  as  well  as  the  shell 
is  produced  by  the  shell-glands  of  the  mantle.     The  value  of  the 


PELECYPODS  431 

pearl  is  based  on  the  brilliancy  of  the  nacre,  the  size,  and  the  form. 
Luster,  or  "  orient,"  is  to  the  pearl  what  brilliancy  is  to  the  dia- 
mond. The  round  form  has  the  greatest  value,  next  the  pear- 
shape,  and  lastly  the  oval.  Pearls  of  inferior  value  are  produced 
by  other  species  than  Meleagrina  margaritifera,  the  true  pearl-oyster. 
Many  bivalves  secrete  similar  bodies,  but  as  they  have  the  nature 
of  the  shell,  those  produced  by  moUusks  having  lusterless  inte- 
riors are  of  no  value.  Beautiful  pink  pearls  are  found  in  the 
gasteropod  Stromhus  gigas,  the  conch-shell  of  the  West  Indies. 
The  shells  of  the  pearl-oyster  are  themselves  very  valuable,  being 
the  ''mother-of-pearl"  nsed  in  the  manufacture  of  buttons, knife- 
handles,  inlay-work,  and  so  on.  They  have  three  grades  of  com- 
mercial value ;  of  the  &st  are  the  ''  silver-lipped,"  from  the  South 
Seas,  of  the  second  the  "  black-lipped,"  from  Manila  and  Ceylon, 
and  of  the  third  the  ''bullock-shells,"  from  Panama. 

Genus  Avicula 

A.  atlantica,  A  Floridian  species  which  is  often  found  attached  by 
its  byssus  to  large  algae  which  have  been  washed  upon  the  beach.  The 
sheh  is  reddish -brown,  with  many  white  radial  lines.  Its  obliquely  oval 
shape,  the  long  wing-like  extension  of  the  dorsal  margin,  the  inequivalve 
shells,  and  the  byssal  sinus  placed  just  below  the  forward  extension  of 
the  hinge,  are  characteristics  which  will  enable  one  to  recognize  the  spe- 
cies at  once.  The  structure  of  the  shell  is  unusual  in  being  so  largely 
composed  of  organic  matter  that  it  possesses  elasticity  near  its  thin- 
ner edges. 

Genus  Pinna 

J*,  muricata  and  -P.  seminiida.  Two  species  of  this  family  which 
are  very  abundant  in  Floridian  waters  and  are  often  to  be  found  asso- 
ciated upon  the  muddy  or  sandy  shores  of  bays.  Like  Modiola  plicatulaj 
they  attach  themselves  by  means  of  their  byssus  to  shells  or  stones 
which  lie  under  the  surface.  With  the  pointed  end  of  the  shell  directed 
downward,  they  remain  almost  wholly  concealed  in  the  sand.  Only 
about  one  quarter  of  an  inch  of  the  broad  end  of  the  shell  projects 
above  the  sand.  The  edges  of  the  valves  are  as  sharp  as  knife-blades, 
and  great  caution  must  be  used  while  waUdng  barefooted  along  a  beach 
inhabited  by  Pinna.  The  sheUs  of  both  species  are  of  a  triangular 
wedge-shape  and  are  composed  of  a  translucent  crystalline  matter. 
P.  muricata  is  beset  with  triangular  erect  scales  which  project  out 
like  spines.  Their  edges  are  also  sharp  like  pieces  of  broken  glass. 
P,  seminuda  also  has  these  raised  scales,  but  they  are  far  more  numer- 


452  MARINE  INVERTEBRATES 

ous  and  mucli  smaller,  and  are  arranged  in  closely  packed  radiating 
rows,  the  scales  becoming  obsolete  near  the  nmbones.  The  mantle  of 
the  animal  is  doubly  fringed,  and  much  decorated  upon  that  portion 
which  may  be  protruded  from  the  shell.  The  posterior  adductor  is  very 
large  and  strong ;  the  anterior  one  has  almost  disappeared.  The  foot 
is  long  and  slender,  but  is  evidently  a  useless  appendage,  for  the  ani- 
mal's habit  is  stationary.  The  byssus  is  large  and  very  strong.  Gloves 
have  been  made  from  the  byssal  fibers  of  Pinna  mixed  with  silk.  The 
gills  are  very  long  and  are  distinctly  not  filamentous,  the  adjacent  fila- 
ments being  clearly  united  by  vascular  channels.  A  very  curious  develop- 
ment of  the  osphradium  (see  page  339)  into  an  erectile  process  capa- 
ble of  projection  beyond  the  margin  of  the  shell  is  a  unique  feature  of 
Pinna.  Sometimes  thousands  of  pinnas  are  torn  loose  by  storms  and 
cast  upon  the  beaches.  They  do  not  range  north  of  Hatteras.  (Plate 
LXXIX.) 

m 

Genus  I*ema 

P.  ephippium.  A  West  Indian  shell,  also  quite  common  on  the  east 
coast  of  Florida,  and  especially  upon  the  Keys.  It  attaches  itself  by  the 
byssus  in  great  bunches  to  mangrove  roots,  sticks,  and  all  manner  of 
rubbish  in  brackish  water.  It  has  a  very  flat,  irregularly  shaped  shell 
of  a  horn-color,  and  is  from  two  to  three  inches  across.  The  distinguish- 
ing feature  of  Perna  is  the  hinge.  It  is  straight  and  without  teeth,  but 
is  marked  by  a  row  of  transverse  grooves  to  which  the  Hgament  is 
attached.     These  grooves  constitute  a  row  of  cartilage-pits. 


Family  ostreid^ 

This  family  probably  interests  more  people  than  any  other  one 
in  the  class  save  AviculidcB.  The  latter  furnishes  the  pearl- 
oysters,  the  former  the  edible  oysters,  the  two  thus  appealing  to 
two  very  strong  human  cravings — those  of  vanity  and  hunger. 

Few  realize  what  an  enormous  business  the  oyster  trade  has 
become  in  the  United  States.  The  value  of  it  is  stated  to  be  over 
thirteen  million  dollars  annually,  twenty-five  million  bushels  of 
oysters  being  taken  from  the  Chesapeake  alone.  The  edibility  of 
the  oyster  has  been  known  from  early  times,  for  vast  heaps  of  empty 
oyster-shells,  known  as  kitchen-middens,  occur  in  various  parts 
of  the  world.  Some  of  them  are  of  such  size  and  extent  as  to 
warrant  the  belief  that  their  formation  must  have  required  cen- 
turies. Shell-mounds  are  found  along  the  coasts  of  Florida  and 
are  of  some  archgeological  value.  The  cultivation  of  oysters  as 
recorded  by  Pliny  dates  from  the  first  century  B.C.,  at  which 


PLATE   LXXIX. 


Pinna  rauricata. 
Pinna  seminnda. 
Pecten  hastatus. 


PELECYPODS  433 

time  a  Roman  named  Sergins  Grata  first  cultivated  oysters  at 
Bai^.  The  aciiteness  of  the  gastronomic  sense  of  a  Roman 
epicure  is  thus  described  by  Juvenal : 

He  could  teU 
At  the  first  mouthful  if  his  oysters  fed 
On  the  Rutupian  or  the  Lucrine  bed 
Or  at  Cireeii. 

The  poet  Gay's  opinion  is  expressed  thus : 

The  man  had  sure  a  palate  cover' d  o'er 

With  brass  or  steel,  that  on  the  rocky  shore 
First  broke  the  oozy  oyster's  pearly  coat, 
And  risk'd  the  living  morsel  down  his  throat. 

The  methods  employed  in  oyster-farming  resemble  those  of 
agriculture,  in  that  the  bed  is  prepared,  seed  is  sown,  superfluous 
and  foreign  growths  are  weeded  out,  enemies  are  driven  off,  and 
the  crop  is  harvested  at  stated  seasons.  The  oyster  is  ovovivipa- 
rous ;  that  is,  it  retains  its  eggs  until  they  are  partly  matured. 
These  are  held  in  the  gills  and  mantle  folds  until  the  time  of 
spawning,  which  begins  in  May  and  lasts  through  the  summer 
months.  The  larv«  are  ejected  as  ciliated  spheres,  called  spat, 
and  swim  freely  about  for  some  time,  often  several  days,  before 
finding  a  resting-spot.  The  03^ster-grower  secures  many  of  the 
larvae  by  placing  in  their  way  substances  to  which  they  can 
attach  themselves.  The  American  culturist  strews  his  carefully 
prepared  beds  with  empty  oyster-shells,  on  which  the  spat  settle, 
and  the  seed  is  thus  secured;  for  the  spat,  once  fastened,  lose 
the  power  of  locomotion  and  become  fixed.  At  the  end  of  a 
year  the  shells  which  hold  the  young  oysters  (now  about  an  inch 
long  and  called  "fry")  are  taken  up,  and  the  fry  are  thinned  out 
and  replanted,  or  are  sold  to  other  oyster-farmers. 

During  the  period  of  their  growth  the  oysters  are  sometimes 
transplanted  several  times.  At  the  end  of  three  to  five  years  they 
have  attained  marketable  size,  and  the  beds  are  then  harvested 
and  prepared  for  another  crop.  Some  oystermen  have  several 
acres  of  bottom  under  cultivation.  These  areas  are  obtained  by 
purchase  or  grant  from  the  State,  and  their  limits  are  as  defined 

28 


434  MARINE  INVERTEBRATES 

as  are  the  fenced-off  acres  of  upland  meadows.  Tlie  business  of 
the  oyster-culturist  is  to  plant  the  young  oysters  and  watch  their 
development,  keeping  the  beds  thinned,  that  the  oysters  may 
not  be  too  crowded  for  their  normal  and  symmetrical  growth, 
and  protecting  them  from  their  enemies,  of  which  there  are  many. 
The  principal  enemies  of  the  oyster  are  the  starfish  and  the  pre- 
daceous  mollusks  Tlrosalpinx  and  Nassa.  Whole  beds  have  been 
known  to  be  destroyed  in  a  single  night  by  the  visitations  of 
starfishes,  hence  a  constant  watchfulness  is  required  on  the  part 
of  the  oysterman.  Policing  the  oyster-farms  is  another  of 
his  cares,  for  pirates  abound,  and  a  bed  may  be  robbed  in  the 
night  as  easily  as  an  orchard  may  be  despoiled  of  its  fruit.  Oys- 
ter-culture is  carried  on  extensively  in  Long  Island  Sound,  on  the 
coasts  of  New  Jersey  and  Virginia,  and  in  the  Chesapeake  Bay. 
The  oysters  from  certain  localities  are  esteemed  more  than  others, 
the  flavor  of  the  oyster  being  very  dependent  upon  the  purity 
of  the  water  and  on  the  organisms  upon  which  it  feeds.  It  has 
been  definitely  shown  that  oysters  grown  in  contaminated  waters 
have  been  the  agents  of  transmitting  disease,  notably  typhoid 
fever  and  cholera. 

Oyster-culture  has  reached  the  highest  degree  of  perfection  in 
France,  where  miles  of  muddy  shores  left  by  the  ebb-tide  are  uti- 
lized for  the  purpose.  The  famous  pare  at  Arcachon,  covering 
ten  thousand  acres,  illustrates  the  system  generally  practised. 
The  spat  is  there  collected  on  tiles  coated  with  cement,  piled  in 
layers  crosswise,  and  secured  in  crates.  These  tiles  are  exposed 
in  favorable  localities  and  collect  the  swimming  embryos.  The 
rough  cement  holding  the  spat  is  then  chipped  off  the  tiles  and 
placed  in  wire  trays.  These  ambulances,  or  caisses  ostreopMles, 
placed  between  short  posts,  protect  the  fry  from  their  ene- 
mies. At  low  tide  the  young  oysters  are  carefully  examined 
and  sorted,  and  at  the  right  age  they  are  removed  to  open  areas. 
The  pare  is  divided  into  regular  squares  by  canals  of  suitable 
width,  some  of  the  squares  having  banks  and  gates  to  retain  the 
water  of  the  receding  tide  if  desired.  Each  man's  pare  is  sepa- 
rated from  that  of  his  neighbor  by  canals  of  greater  width,  and 
often  by  stakes  having  a  few  branches  on  the  ends.     These  pi- 


PELECYPODS  435 

gnons,  which  sway  in  the  wind,  are  said  to  frighten  away  the  pre- 
daceous  ray  which  is  apt  to  hover  about  the  preserves.  The 
pares  are  finally  thinned  out  by  sending  the  oysters  to  other 
pares  to  be  fattened.  There  is  a  celebrated  2^a7x  cVelevage  at 
Marennes.  It  is  a  collection  of  artificial  ponds,  the  floors  of 
which  are  covered  with  algae,  which  harbor  vast  numbers  of 
diatoms  and  other  microscopic  organisms  on  which  the  oysters 
feed.  The  green  diatom  {N'avimda  ostrearia)  gives  to  the  oysters 
of  Marennes  the  green  color  and  peculiar  flavor  which  is  so  much 
esteemed  by  the  epicures  of  France.  To  the  American,  however, 
the  green  oyster  is  not  acceptable. 

Genus  Ostrea 

O,  virginica.  A  description  of  this  species,  our  common  oyster,  is 
hardly  necessary.  Every  one  has  seen  the  rough,  shaggy,  unlovely 
shell.  The  hinge  is  toothless,  but  has  a  wide  depression  for  the  liga- 
ment. The  animal,  having  stationary  habits,  has  practically  no  foot  at 
all.  There  is  but  one  large  adductor  muscle,  around  which  curve  the 
gills,  the  latter  being  united  to  each  other  posteriorly.  The  mantle 
margin  is  finely  and  doubly  fringed.  Although  Ostrea  is  a  stationary 
mollusk,  it  has  no  byssus. 

0.  virginica  has  been  introduced  at  San  Francisco,  where  it  lives 
well,  but  does  not  seem  to  multiply  very  rapidly.  The  native  species, 
O.  lurida,  is  about  two  inches  long,  dark  in  color,  and  stained  a  pur- 
plish hue.      It  is  not  very  delicately  flavored. 

O.  frons.  This  species  has  a  thinner  shell  than  0.  virginica.,  with 
coarsely  serrated  margins.  It  occurs  in  beds  in  the  neighborhood  of 
mangroves  all  along  our  South  Atlantic  shores.  It  cannot  compare 
with  its  Northern  relative  in  flavor,  but,  hke  the  European  Ostrea 
edulis,  it  is  sometimes  ''not  bad." 


Family  pectinidje 
Genus  Pecten 

The  scallop-shells  {Peden)  are  objects  too  familiar  to  require 
any  general  description.  The  rounded  valve,  usually  ornamented 
with  radiating  ribs,  and  the  wing-like  projections  (called  ^^ears")? 
from  each  side  of  the  umbonal  region,  are  never-failing  char- 
acters. The  outline  of  Peden  has  been  considerably  employed 
in  conventional  designs  for  mural  decorations ;  indeed,  the  figure 


436  MARINE  INVERTEBRATES 

of  a  well-known  Mediterranean  pecten  (P.  jacohius),  found  com- 
monly in  Palestine,  became  an  emblem  of  religious  significance 
during  the  middle  ages.  Returning  crusaders  fastened  to  their 
garments  a  specimen  of  "St.  James's  shell"  as  an  evidence  of  the 
fact  that  they  had  been  to  the  Holy  Land,  and  the  design  of  the 
shell  came  to  be  adopted  upon  many  coats  of  arms  and  also  in  the 
insignia  of  various  orders  of  devout  and  adventurous  knights  of 
the  middle  ages. 

The  animal  is  of  the  highest  type  of  monomyarian  moUusks, 
that  is,  of  bivalve  mollusks  with  only  a  single  adductor  muscle. 
Unlike  most  pelecypods,  which  have  a  very  small  foot,  Feden 
rarely  has  a  byssus,  and  is  neither  a  stationary  nor  a  sluggish  crea- 
ture. It  can  propel  itself  through  the  water  by  spasmodically  clos- 
ing and  opening  its  valves,  in  an  eccentric,  darting  sort  of  flight, 
though  most  of  the  time  it  rests  quietly  upon  the  bottom.  The 
mantle  is  entirely  open  and  highly  ornate  about  its  margin, 
which  is,  furthermore,  the  seat  of  many  eyes,  capable,  appa- 
rently, of  no  mean  degree  of  vision.  The  adductor  muscle  is  very 
large  and  strong,  and  occupies  a  central  position,  about  which  the 
gills  circle ;  the  latter  are  plainly  filamentous. 


J*,  magellanicus.  The  largest  of  the  east-coast  species  of  Pecten. 
It  is  a  Northern  species,  and  was  long  known  by  the  name  of  -P.  tenu- 
iscostatus  —  a  name  given  to  it  on  account  of  its  very  numerous  radiat- 
ing strife }  but  it  was  later  discovered  that  the  North  Atlantic  form  was 
in  reality  the  same  as  the  P.  magellanicus  of  Patagonia.  The  latter  being 
the  older  name  and  entitled  to  priority,  our  shell  became  P.  magellanicus, 
the  other  name  falling  within  its  synonymy.  The  length  and  height  of 
this  scallop  are  from  five  to  five  and  a  half  inches.  One  valve  is  more 
convex  and  slightly  larger  than  the  other,  the  smaller  being  lighter  in 
color.  The  valves  gape  considerably  along  their  upper  margin  below 
the  hinge.  The  cartilage-pit  is  deep.  North  of  Cape  Ann  this  large 
species  is  of  common  occurrence  in  moderately  deep  water.  The  deeper 
bays  and  arms  of  the  sea  which  everywhere  penetrate  the  Maine  coast 
are  its  favorite  resorts.  A  good  way  to  catch  pectens  is  to  lower  a  fishing- 
line  at  a  spot  where  the  fishermen  report  "  scallop-ground,"  and  drag  it 
along  over  the  bottom.  Sooner  or  later  it  will  enter  the  open  shell  of 
some  pecten,  which  will  instantly  close  its  valves  upon  the  string  and 
allow  itself  to  be  drawn  out  of  the  water.  In  Maine  these  large  scallops 
are  eaten,  but  they  have  not  found  great  favor  in  the  city  markets.  In 
color  they  vary  from  reddish  through  brown  to  ashen. 

P.  islandicus,  A  species  not  so  large  as  the  last,  with  more  promi- 
nently raised  ribs  (about  fifty  to  one  hundred  in  numljer),  which  are  cov- 


PELECYPODS 


437 


ered  with  a  multitude  of  erect  scales.  The  ribs  persist  upon  the  interior  of 
the  shell.  The  "  ears  "  are  unequal  in  size.  The  color  is  light  orange  to 
reddish-brown,  with  zones 
of  darker  and  richer  col- 
or. One  valve  is  flatter 
than  the  other  and  more 
lightly  colored.  Greatest 
length  about  three  inches ; 
height  three  and  a  half 
inches.  This  is  a  Northern 
shell,  belonging  to  the 
waters  of  Newfoundland, 
but  its  valves  are  fre- 
quently cast  upon  the  New 
England  beaches. 

P.  irradians.  The 
common  shallow-water 
species  of  the  Atlantic 
coast.  This  exceedingly 
abundant  species  does 
not  range  north  of  Bos- 
ton, but  finds  an  exten- 
sive habitat  to  the  south. 
Its  metropolis  is  Cape 
Cod,  Long  Island  Sound, 
and  the  Jersey  coast 
waters.     This  is  the  true 

scallop  of  the  Boston  and  New  York  markets.  Only  the  adductor 
muscle  is  eaten.  In  this  species  there  is  not  so  marked  a  difference  in 
the  convexity  of  the  two  valves.  There  are  about  twenty  elevated  and 
rounded  ribs,  the  spaces  between  them  being  also  rounded.  The  color 
is  variable,  from  a  blackish  horn  to  ashen  gray.  The  "  ears  "  are  equal ; 
the  interior  is  shining,  and  grooved  to  correspond  with  the  external  ribs. 
Length  two  and  three  fifths  inches,  height  two  and  a  half  inches.  On 
clear,  calm  days  the  immature  individuals  of  this  species  may  often  be 
seen  in  shallow  water  disporting  themselves  most  gaily,  skipping  about 
and  snapping  their  valves  in  great  glee.  Their  mantle  margins  are  very 
ornate  in  scarlet  or  orange,  with  rows  of  bright-blue  eyes.  Care  must 
be  taken  in  handling  scallops,  especially  the  large  P.  magellanicus,  for  a 
finger  caught  between  the  valves  will  be  badly  bruised. 

J*,  dislocatus.  South  of  Hatteras  this  species  takes  the  place  of  its 
Northern  relative,  P.  irradians.  It  is  somewhat  more  globular  and  per- 
haps not  quite  so  large,  but  the  resemblance  between  the  two  species  is 
very  marked.  It  has  from  twenty  to  twenty-two  rounded  ribs,  with  very 
numerous  concentric  wrinkles  between  them.  In  color  it  is  white,  tinged 
with  purple  or  yellow,  with  occasionally  a  system  of  blood-red  lines 
crossing  the  ribs  transversely.  The  diameter  is  about  one  and  a  half 
inches.  This  species  has  the  same  playful  habits  as  P.  irradians,  and  is 
not  at  all  easy  to  capture.  When  pursued  it  dives  into  the  mud,  and  sets 
up  such  a  commotion  by  the  spasmodic  opening  and  shutting  of  its 
valves  that  the  water  at  once  becomes  roiled,  and  the  scallop  is  safely 
hidden  in  its  murky  depths. 


Pecten  islandicus. 


438 


MARINE  INVERTEBRATES 


J*,  hastatus.  There  are  several  very  beautiful  pectens  on  the  Pacific 
coast  of  the  United  States,  and  two  of  these — one  of  northern  and  the  other 
of  southern  range  —  resemble  very  closely  the  two  Atlantic  species  of 
relatively  north  and  south  range,  P.  islandicus  and  P.  irradians  or  dislo- 
catus.  The  first  is  P.  hastatus  of  Puget  Sound.  Valves  of  this  exquisite 
shell  are  even  occasionally  found  in  California.     It  has  very  much  the 

aspect  of  P.  islandicus  — 
unequal  ears  and  an  ovate 
form.  The  most  curious 
thing  about  this  shell  is  the 
fact  that  a  different  system 
of  sculpturing  exists  upon 
the  two  valves.  Upon  one 
the  ribs  are  even  and  the 
whole  surface  is  covered 
with  raised  scales;  upon 
the  other  the  ribs  are  alter- 
nately of  large  and  small 
size.  Color  rose-pink,  with 
deeper  bands;  one  valve 
lighter-colored,  suffused 
with  delicate  pink.  Height 
two  and  a  half  inches. 
(Plate  LXXIX.) 

jP,  ceqtiisulcatus.  The 
Southern  species  above  re- 
ferred to  as  resembling  P. 
irradians  or  dislocatus.  It 
has  about  twenty  stout, 
well-rounded  ribs,  with  concentric  wrinkles  between  them.  The  "  ears  " 
are  equal.  The  size  and  shape  are  as  in  P.  irradians.  The  coloring  is 
whitish,  varying  to  shades  of  brown,  and  excentrically  marked  with 
spots  or  waving  transverse  lines  of  chestnut  or  horn. 


Pecten  irradians,  typical  form. 


ORDER   EULAMELLIBRANCHIATA 

With  the  pectens  we  leave  behind  all  pelecypods  with  the 
true  filamentous  type  of  gill.  In  the  order  Eidamellibranchi- 
ata  we  find  all  the  families  to  be  possessed  of  the  basket- 
work  or  crisscross  branchial  structure.  Each  gill  is  fun- 
damentally formed  of  filaments  which  project  downward,  and 
then  suddenly  turn  upon  themselves  and  ascend ;  the  ascending 
and  descending  limbs  are  connected,  however,  by  processes  of 
presumably  vascular  function,  and  adjacent  filaments  are  con- 
nected by  truly  vascular  channels.  The  closer  connection  of  the 
filaments  to  form  of  each  gill  a  sort  of  plate  is  further  effected 


PELECYPODS  439 

by  connective  tissue,  which  sometimes  is  dense  enough  (though 
always  porous)  to  obscure  the  reticulated  appearance  of  the 
organ.  Furthermore,  the  edge  of  the  outer  lamella  of  the  outer 
gill  unites  with  the  mantle ;  likewise  the  edge  of  the  inner  lamella 
of  the  inner  gill  unites  with  the  body-mass,  and  iehind  the  hody- 
mass  with  the  gills  upon  the  other  side  of  the  animal.  This 
union  of  the  four  gills  in  a  straight  median  line  behind  the  foot 
and  body-mass  forms  a  septum,  which  divides  off  from  the  mantle 
cavity  a  '' suprabranchial"  cavity.  Into  this  cavity  the  excreta 
are  discharged,  and  with  it  the  anal  or  excurrent  siphon  con- 
nects. The  branchial  or  incurrent  siphon  thus  pours  its  current 
of  water  into  the  loiver  mantle  cavity,  to  bathe  the  gills  and  feed 
the  mouth,  while  the  fresh  water  is  not  contaminated  by  any 
open  and  wide  connection  with  the  excretory  processes.  In 
many  of  the  forms  where  the  siphons  are  very  long  and  united, 
this  septum,  formed  by  the  union  of  the  dorsal  edges  of  the  inner 
gills  back  of  the  foot,  is  continued  far  into  the  siphons,  consti- 
tuting the  division  of  the  two  into  the  anal  and  branchial 
siphons. 

Another  feature  of  this  order  is  the  marked  tendency  to  man- 
tle fusion.  As  there  are  always  siphons,  the  mantle-edges  must 
necessarily  have  fused  at  two  points  at  least,  in  order  to  have 
formed  the  siphons.  The  tendency,  however,  is  for  the  fusion  to 
continue,  narrowing  the  pedal  opening  more  and  more,  as  though 
the  mantle  were  endeavoring  to  envelop  the  entire  animal  in  a 
bag  or  sac  open  only  at  one  end  (siphonal  opening),  but  yet 
slightly  ripped  along  one  seam  (pedal  opening). 

This  order  includes  the  great  majority  of  pelecypods,  and  admits 
of  many  very  confusing  modifications  in  its  most  essential  features. 

Family  carditidje 

In  this,  the  first  family  of  the  order,  most  of  the  characteristic 
features  just  spoken  of  are  present.  Mantle  fusion,  however,  has 
not  progressed  beyond  a  degree  which  is  just  sufficient  to  form 
the  siphons.  There  is  a  byssiferous  gland.  The  name  Carditidce 
refers  to  the  heart-shape  of  the  shells. 


440  MARINE  INVERTEBRATES 

Genus  Cardita 

C,  borealis.  A  very  common  species  north  of  Cape  Ann,  reported 
also  in  deeper  water  as  far  south  as  Hatteras.  It  is  a  soHd,  obhquely 
heart-shaped  shell,  with  beaks  elevated  and  turned  forward.     It  has 

about  eighteen  to  twenty  rounded  radiating  ribs, 
which  are  broader  than  the  grooves  between 
them.  The  epidermis  is  rusty-brown.  The  hinge 
is  strong,  with  two  prominent  teeth ;  the  mar- 
gins of  the  shell  are  strongly  crenulated  within. 
Length  one  inch ;  height  about  the  same.  This 
is  not  strictly  a  between-the-tides  species,  but 
its  valves  are  often  cast  upon  the  beaches.  Fine 
specimens  may  be  obtained  by  dredging  at  Bar 
Harbor  or  Eastport. 

C,  floridana,     A   very  common   Floridian 
^   ^.,   ^      ,.       ,     ,  .        species.     Its  seventeen  or  eighteen  ribs  are  very 

Caraita  ooreahs,  nattu-al  size.      -.^  -,  ttittji 

heavy,  and  are  rendered  nodulous  by  the  numer- 
ous bluntly  raised  scales  upon  them.  The  shell  is  lengthened,  and  has  a 
Avell- defined  lunule  and  an  external  ligament.  In  color  it  is  yellowish- 
white,  with  purple  markings  when  young.  Length  one  inch ;  height  three 
fourths  of  an  inch.  It  lives  in  sheltered  bays ;  detached  valves  are 
often  found  cast  upon  the  beach. 

Faiviily  astartid^ 

Genus  As t arte 

Notwithstanding  their  rather  small  size,  there  is  a  trimness 
about  the  shells  of  Astarte  which,  taken  together  with  their 
rich  chestnut  epidermis,  makes  them  very  interesting  and  desira- 
ble additions  to  the  cabinet.  The  family  is  one  of  cold-water 
range,  with  a  few  representatives  on  the  New  England  coast. 
Live  specimens  are  not  easily  captured,  for  they  live  in  deeper 
water  than  one  would  care  to  wade  in,  nevertheless  they  are  fre- 
quently cast  upon  the  beaches  after  storms.  The  animal  has  a 
very  short  efferent  siphon,  large  labial  palps,  and  very  obliquely 
placed  gills.  Not  more  than  twenty  living  species  of  Astarte  are 
known,  and  all  of  them  belong  in,  or  are  wanderers  from,  polar 
seas.  Fully  three  hundred  fossil  species  of  this  genus  have  been 
described  from  Mesozoic  rocks  in  all  parts  of  the  world.  The 
question  naturally  arises  whether  in  these  its  dying  days  Astarte 
has  sought  colder  waters  in  which  to  pass  its  remaining  existence, 
or  whether  climates  have  changed.     The  fact  that  such  strictly 


PELECYPODS 


441 


tropical  genera  as  Yoluta  and  Co7ius  are  found  fossil  in  northern 
Siberia  seems  to  be  evidence  in  proof  of  great  climatic  variations. 


A,  castanea.  This  species  has  a  thick  and  heavy  shell  for  one  so 
small,  with  round  ventral  margins  and  prominent  beaks.  The  surface 
is  very  slightly  undulated  and  is  covered  with  a  thick 
chestnut  epidermis  with  pale  and  dark  zones.  The 
hinge  is  broad  and  flat,  with  a  prominent  cardinal 
tooth  upon  the  right  valve,  which  accurately  fits  into 
a  pit  formed  by  two  teeth  on  the  left  valve.     Length 


one  inch ;  height  one  inch. 

A,  ti7idata,  A  species  slightly  larger 
than  the  last,  with  ten  to  twenty  promi- 
nent concentric  undulations. 

The  identification  of  the  many  species 
of  Astarte  often  becomes  exceedingly  difficult  on  account 
of  the  fact  that  the  genus  is  a  remarkably  uniform  one  in 
its  main  characters  and  is  infinitely  variable  in  its  minor  details. 


Astarte  castanea. 


Astarte  undata. 


Family  cyprinid^ 


Genus  Arctica 

This  family  is  represented  by  one  species  upon  the  New  Eng- 
land coast,  which  is  much  songht  after  by  collectors.  It  is  one 
of  the  larger  clams, 
but  is  too  uncommon 
to  have  received  a 
popular  name  and  to 
be  generally  well 
known  by  the  fisher- 
men along  the  shore. 


A,  (Cyprina)islan- 
dica.  This  clam  has  a 
thick  though  not  pon- 
derous shell,  with  promi- 
nent beaks  and  a  stout, 
prominent  ligament. 
Its  cardinal  teeth  are 
large,  but  its  laterals  are 
very  small.  A  striking 
feature  of  this  species, 
which  at  once  separates 


Arctica  (Cyprina)  islandica. 


442  MARINE  INVERTEBRATES 

it  from  all  other  shells  of  our  coast  of  similar  size,  is  the  coarse,  wrinkled 
epidermis  of  black  to  chestnut  color.  The  shell  is  very  suggestive  of  a 
large,  overgrown  Astarte.  Length  three  and  a  half  inches;  height 
three  inches.  It  is  found  of  all  sizes,  down  to  one  fourth  of  an  inch  in 
diameter,  upon  muddy  stations  in  moderately  deep  water  near  the 
mouths  of  rivers  -,  but  the  surest  way  to  get  it  is  to  search  the  beach 
after  a  hard  onshore  gale. 

Family  lucinid^ 

This  family  finds  its  metropolis  in  warmer  waters,  and  the  best 
representatives  of  it  must  be  sought  for  upon  the  Floridian 
beaches  or  in  the  shallow  bays  of  that  sandy  coast.  A  long  ver- 
miform foot  is  a  characteristic  of  the  animal,  as  is  also  the  fact 
that  at  times  there  is  only  a  single  gill  upon  each  side  of 
the  body.  In  some  of  the  Lucinidce,  more  so  than  in  most  other 
pelecypods,  the  chief  function  of  the  gills  is  to  furnish  a  brood- 
ing-place for  the  thousands  of  ova  which  the  creatures  generate. 
Sometimes  a  Lucina  will  be  captured  with  the  gills  swollen  out  of 
all  proportion,  and  literally  stuffed  with  tiny,  microscopic  eggs. 
At  such  times  the  gills  lose  all  semblance  of  branchial  organs. 
The  shells  are  orbicular,  with  depressed  small  umbones,  a  distinct 
lunule,  a  semi-external  ligament,  two  cardinal  teeth,  and  laterals 
(a  variable  feature).  There  is  no  pallial  sinus.  The  color  is 
white,  and  the  outlines  are  rounded. 

Genus  Lucina 

Zi.  tigrlna.  The  largest  of  the  group,  measuring  three  inches  across 
and  nearly  the  same  in  height.  It  is  flatly  convex  and  radially  ribbed 
by  a  great  number  of  costee  which  are  crossed  and  decussated  through- 
out with  concentric  ridges.  The  color  is  white.  This  fine  shell  lives 
only  in  southern  Florida  and  is  abundant  in  shallow  water  on  sandy  sta- 
tions.    (Plate  LXXX.) 

L,  floridana.  One  of  the  most  abundant  bivalves  in  Florida,  often 
cast  in  thousands  upon  the  beaches.  It  lives  in  shallow  protected 
waters  and  upon  sand-flats  which  are  partly  exposed  at  low  tide.  It 
has  the  usual  round  outlines  of  the  genus,  with  exceedingly  small  um- 
bones, directed  forward,  and  a  smooth  surface,  save  for  fine  growth- 
lines  of  a  light  straw-color.  The  shell  is  pure  white.  Diameter  about 
one  inch.     (Plate  LXXX.) 

i.  pennsylvanica.  A  species  often  associated  with  the  last,  but  about 
twice  as  large.  Its  thin  but  tough  epidermis  clings  to  the  shell  in  raised 
concentric  lines,  giving  it  a  circularly  ribbed  appearance.  The  most 
prominent  feature  of  this  species  is  a  depressed  line  upon  either  valve 
extending  obliquely  from  the  umbones  to  the  posterior  ventral  margin, 


PELECYPODS  443 

causing,  at  the  margin,  a  pucker  or  break  in  its  even  continuity.  The 
lunule  is  large  and  ribbed ;  the  teeth  are  small ;  the  color  is  pure  white, 
with  a  light  straw-tinted  epidermis.    (Plate  LXXX.) 

L,  dentata.  In  this  species  the  shells  are  thin 
and  white,  with  well-marked  concentric  lines  crossed 
by  deep  oblique  narrow  furrows  bent  at  nearly 
right  angles  to  the  lines  of  growth  and  forming  teeth 
around  the  margin.     Found  along  the  entire  coast. 

L,  californica.  The  best-known  California 
species  of  this  genus.  It  is  pure  white,  with  fine 
concentric  lines,  and  varies  in  size  from  one  half 
of  an  inch  to  one  and  a  half  inches  in  diameter.  ^    .     ,   ^  , 

The  lateral  teeth  are  the  stronger,  and  the  lunule  is 
upon  the  right  valve  only.     With  these  exceptions  this  species  preserves 
the  usual  characters  of  this  genus. 

L,  nuttallii,  belonging  to  the  southern  shores  of  California,  is  decus- 
sated like  fine  wickerwork.  The  sheU  is  flattened  and  ridged  along  the 
hinge-margin.  The  color  is  white.  Diameter  about  one  inch  in  large 
specimens.     (Plate  LXXX.) 

Genus  Loripes 

L,  edentula.  A  species  which  is  seldom  captured  alive.  Its  home  is 
in  the  open  sea,  but  vast  quantities  of  its  valves  are  occasionally  thrown 
upon  the  beaches  south  of  Hatteras,  as  far  as  the  Gulf  of  Mexico.  On 
account  of  the  weak  hinge  ligament,  the  valves  become  easily  separated, 
and  it  is  not  always  easy  to  find  two  that  will  exactly  match.  Loripes 
preserves  the  same  circular  outlines  as  Lucina,  but  is  more  ventricose, 
and  the  hinge  and  teeth  are  very  feeble.  This  species  is  a  little  over  two 
inches  in  length  and  slightly  under  two  inches  in  height.  It  is  pure 
white  without,  and  is  finely  striated  with  growth-lines ;  bright  orange 
within,  especially  about  the  pallial  line  and  muscle-scars.  (Plate 
LXXX.) 

Family  tellinid^ 

Genus  Tellina 

If  V7e  should  create  an  aristocracy  of  beauty  among  the  bivalves, 
as  has  been  done  by  conchologists  among  the  gasteropods,  this 
family  wonld  deserve  high  rank.  Most  of  the  American  species 
of  Tellina  are  too  small  to  impress  one  very  greatly  with  their 
beauty,  but  in  the  West  Indies  and  in  the  tropical  Pacific  waters 
are  some  wonderfully  handsome  shells  belonging  to  this  or 
to  the  allied  genus  Macoma.  However,  we  have  in  Florida  the 
very  striking  T.  radiata,  a  truly  beautiful  shell,  which,  were  it 
less  common,  would  be  highly  prized  in  collections.  Rarity,  no 
doubt,  adds  a  wonderful  luster  to  shells  as  well  as  to  gems.    The 


444  MARINE  INVERTEBRATES 

animal  of  Tellina  has  long,  slender  siphons,  which  are  separate. 
The  gills  are  small,  and  the  outer  lamella  or  branchial  fold  is 
directed  dorsally.  Although  the  foot  shows  evidences  of  a  bys- 
sogenous  gland,  there  is  no  actual  byssus.  The  shells  are  por- 
celanous  and  translucent,  equivalve,  with  an  external  ligament, 
and  at  least  two  cardinal  teeth  in  each  valve. 

T.  radiata.  This  species  varies  from  three  to  four  inches  in  length, 
and  from  one  and  a  half  to  one  and  three  fourths  inches  in  height.  It  is 
highly  polished,  shining  white,  and  yellowish  about  the  umbonal  region, 
and  has  three  wide  rays  of  bright  pink  extending  from  the  beaks  to  the 
ventral  margin.  On  account  of  its  remarkable  coloration  it  is  called  the 
'^  setting-sun  shell."  Its  surface  is  smooth.  A  common  variety  is  of  a 
uniform  creamy-white  color  with  carnation  beaks.  This  shell  is  always 
offered  for  sale  by  the  marine  curio-  and  shell-dealers  in  Florida  seaside 
resorts,  and  at  Atlantic  City,  Cape  May,  and  elsewhere. 

T,  alternata  resembles  the  last  in  shape,  being  flattish  and  oblong, 
but  it  is  more  pointed  or  angulated  posteriorly.  There  is  also  a  slight 
twist  in  the  posterior  end  of  the  shell.  Its  surface  is  decorated  by  nu- 
merous impressed  concentric  lines.  The  color  is  uniformly  white  or  yel- 
lowish, with  pink  rays.  Length  two  and  a  half  to  three  inches )  height 
two  and  a  half  inches.  Found  from  Hatteras  to  the  Gulf  of  Mexico,  in 
shallow,  sandy  stations  and  on  beaches  after  storms.    (Plate  LXXXI.) 

T.  hodegensis.  The  most  striking  species  of  Tellina  found  on  the 
west  coast,  and  of  rather  northern  range.  It  is  about  two  inches  in 
length,  creamy- white  in  color,  and  ornamented  with  very  fine  concentric 
lines.  A  very  characteristic  feature  of  the  genus  is  present  in  this  spe- 
cies as  in  the  last,  namely,  a  slight  twist  or  bend  to  one  side  in  the  pos- 
terior end  of  the  shell. 

T.  tenera,  A  little  Tellina 
found  in  New  England  waters, 
which,  though  very  small,  is 
worthy  of  mention  on  account 

Telli^Un^ra,.^^.^...         ^       ^^uina  tenera.      of   itS    abuudanCC   UpOU  all  OUr 

beaches  north  of  Hatteras.  It 
is  only  about  half  an  inch  long,  and  sUghtly  over  one  quarter  of  an  inch 
high.  It  may  be  distinguished  by  its  general  generic  characters,  its 
iridescent  surface,  and  its  delicately  marked  lines  of  growth;  some- 
times it  is  rose-tinted.  Its  remarkably  long  siphons  are  shown  in  the 
accompanying  figure. 

Genus  Macoma 

M,  secta,  A  very  pretty  thin  glossy  shell  from  two  to  three  inches  in 
length  and  about  one  fourth  less  in  height,  which  occurs  from  Monterey 
southward.  The  posterior  end  of  the  shell  is  contracted  and  slightly 
bent ;  the  paUial  sinus  is  deep.  There  is  an  external  ligament.  (Plate 
LXXXI.) 

M,  nasuta.  Another  Californian  species,  with  a  less  shining  surface 
and  a  very  thin  light-brownish  epidermis.     The  twisting  of  the  posterior 


PLATE   LXXX. 


1 ,  Lucina  tigrina.  3,  Lucina  pennsylvaniea. 

2,  Lucina  floridana.  4,  Lucina  nuttallii. 

5,  Loripes  edentula. 


PLATE   LXXXI. 


1,  Tellina  alternata.  3,  DoBax  variabilis. 

2,  Macoma  secta.  4,  Donax  calif ornicus. 

5,  Reeta  canaliculata. 


PELECYPODS  445 

margin  is  striking.     It  lias  very  fine  cardinal  teeth.     Length  two  to 
three  inches. 

M,  balticaf  M,  proxuna^  M,  tenia.  The  first  two  of  these  species 
are  dingy  in  color,  and  are  covered  with  a  dirty -looking,  thin  epidermis. 
The  first  has  a  wide  range  to  Norway  and  Scotland,  and  is  exceedingly 
common  all  along  our  coast  from  Maine  to  Georgia. 
It  occurs  plentifully  in  the  Hudson  River  above 
New  York,  and  in  all  sandy  or  muddy  bays.  It  is 
rounded  in  outline,  while  the  next  species  {M. 
proximo)  is  more  pointed  posteriorly.  When  these 
species  are  buried  in  the  sand  their  two  long,  slen- 
der siphons  project  above,  one  supplying  the  animal 
with  a  constant  current  of  fresh  water,  and  the  other 
ejecting  that  which,  having  passed  the  gills  and  Macoma  baiuca. 
labial  palps,  is  exhausted  of  its  air  and  nutriment 
and  contaminated  by  waste  products.  M.  tenia  is 
white,  with  very  fine  lines  of  growth,  and  pohshed 
and  shining  within.  It  is  warped  posteriorly.  Length 
three  fifths  of  an  inch ;  height  two  fifths  of  an  inch.  ^^'^'^^  *''**«• 

Fai^hly  donacidje 
Genus  Donax 

The  DonacidcB  are  represented  upon  our  coasts  by  compara- 
tively few  species,'  all  belonging  to  the  genus  Donax.  The  shells 
are  under  an  inch  in  length,  and  have  a  peculiarly  shortened  an- 
terior portion ;  thus  they  are  inequilateral.  Their  ventral  mar- 
gins are  finely  denticulate.  The  pallial  sinus  is  deep.  There  are 
two  or  three  cardinal  teeth  and  a  variable  number  of  laterals. 

D.  variabilis.  This  httle  shell,  the  common  Floridian  form,  exhibits 
every  imaginable  scheme  of  color-combination,  and  defies  general  or 
comprehensive  description.  Probably  the  most  usual  pattern  developed 
is  a  bluish-white  background  with  purplish  radiating  lines.  Another 
is  a  pure-white  foundation  with  red  lines.  The  surface  is  striated  longi- 
tudinally with  excessively  fine  riblets.  Length  one  half  of  an  inch  or 
slightly  more.  In  March  and  April  these  shells  are  thrown  alive  in 
millions  upon  the  Florida  beaches.  Each  wave  seems  to  be  laden  with 
them,  and  when  the  foaming  waters  of  each  spent  breaker  recede,  the 
little  sheUs  lie  still  upon  the  sand  for  a  moment,  glittering  like  jewels  in 
the  sunlight ;  then,  with  a  sudden  protrusion  of  the  foot  and  a  quick 
turn,  they  all  disappear  like  a  flash,  buried  in  the  sand  before  the  next 
breaker  strikes  them.  One  must  be  very  quick  to  catch  these  active  lit- 
tle moUusks.     (Plate  LXXXI.) 

D,  calif orniciis.  Professor  Keep  very  aptly  describes  this  shell, 
which  is  very  common  in  California,  as  ''  short  and  stumpy,  cut 
nearly  square  off  at  one  end  (anterior),  and  tapering  to  a  rounded  edge 
at  the  other."  The  same  description  fits  both  this  and  the  Floridian  D. 
variabilis  so  well  that  the  two  forms  may  be  one  and  the  same  species. 


446 


MARINE  INVERTEBRATES 


If  they  were  shells  of  arctic  range  it  would  be  easier  to  connect  them ; 
but  as  neither  is  a  cold-water  form,  it  becomes  more  difficult  to  place, 
them  under  one  name.  The  increasing  number  of  similar  species  being 
found  upon  the  Atlantic  and  Pacific  sides  of  Central  America  points 
almost  conclusively  to  the  existence  of  a  waterway  between  the  two 
oceans,  somewhere  between  North  and  South  America,  at  no  very  remote 
geological  period.  Possibly  the  closing  of  some  such  waterway  through 
the  isthmus  connecting  the  oceans  has  separated  these  forms  geographi- 
cally, thus  leading  us  to  separate  them  specifically.     (Plate  LXXXI.) 

Family  mactrid^ 
This  is  a  very  large  faraily  of  universal  distribution  and  with 
a   great  number  of   genera    and   subgenera,  rather  confusedly 
gathered  into  subfamilies.    The  dominant  genus  Mactra  comprises 
the  largest  bivalve  upon  the  east  coast  of  the  United  States. 

Genus  Mactra 

The  mactras  live  in  the  sand  near  the  margin  of  the  water, 
often  upon  the  exposed  open  coast.  The  mantle  is  open,  except 
where  it  is  fused  to  form  the  siphons.  These  are  short  and 
united.  The  outer  gill  is  dorsally  directed ;  that  is  to  sa}^,  it  does 
not  depend  into  the  mantle  cavity  as  does  the  inner  gill,  but 
projects  just  the  other  way;  it  is  also  smaller  than  the  inner  one. 
The  foot  is  strong,  bent,  and  tongue-shaped,  and  no  doubt  well 
adapted  to  the  rough  life  in  the  surf  and  the  heavy,  shifting 
sands.  The  main  characteristic  of  the  mactra  shell  is  the 
prominent  triangular-shaped  fossette,  or  cartilage  plate,  situated 
internally  and  just  under  the  beaks.     The  shells  are  equivalve, 

and  devoid  of  bright 
colors  or  striking 
sculptural  features. 
Internally  the  pallial 
line  is  plain,  and  the 
sinus  well  marked  but 
not  deep. 

M,  solidissima       is 

one  of  the  very  com- 
monest, if  not  the  com- 
monest large  bivalve  of 
the  New  England,  Long 
Mactra  solidissima.  Island,  and  New  Jersey 


PELECYPODS  447 

beaches.  It  is  covered  with  a  thin  brownish  or  straw-colored  epidermis, 
usually  more  or  less  worn  away  in  adult  specimens  and  wholly  absent  from 
the  dead  valves  found  upon  the  beaches.  There  is  a  fragile  V-shaped  car- 
dinal tooth,  which  is  generally  broken  away  in  forcing  open  the  valves ; 
the  lateral  teeth  are  long  and  thin,  and  striated  on  their  receiving  sur- 
faces. The  length  of  this  "giant  clam  "is  from  four  to  seven  inches. 
This  is  the  first  shell  the  collector  will  find  (north  of  Hatteras)  when  he 
goes  to  an  open,  sandy  beach. 

M,  similis.  A  small  variety  of  the  species  last  described,  of  similar 
outline,  but  less  heavy  and  strong.  Its  range  is  from  Hatteras  south- 
ward to  Brazil.  Passing  from  New  Jersey  to  Hatteras,  Mactra  soli- 
dissima  diminishes  in  size,  and  after  passing  that  faunal  barrier  the 
Northern  form  is  entirely  replaced  by  this  Southern  variety.  The  shell 
is  brighter,  though  not  exactly  bright-shining.  Its  habits  are  entirely 
similar  to  those  of  the  Northern  form.  On  the  west  coast  of  Flor- 
ida it  is  the  most  abundant  bivalve  upon  the  beaches. 

M,  oralis,  A  species  of  Northern  range,  which  so  greatly  resembles 
M.  solidissima  as  to  suggest  identity ;  but  the  lateral  teeth  are  smooth 
and  not  striated,  while  the  shell  itself  seldom  attains 
a  length  of  over  four  inches. 

M,  lateralis.  An  exceedingly  common  shell, 
found  in  all  the  salt-marshes  and  tidal  estuaries  of 
our  coast.  It  is  much  smaller  than  the  mactras  just 
described,  being  not  over  one  half  of  an  inch  in 
length.  It  is  white,  and  is  covered  with  a  dirty 
brown  epidermis;  the  hinge  is  strong,  with  deep  Mactra  lateralis. 

cartilage  fossette  and  a  V-shaped  marginal  tooth. 
The  laterals  are  long  and  slender.      The  animal  has  a   strong  foot 
and  two   slender,  long   siphons   which  are  yellow  in  color. 

Genus  Rmta 

It,  (Labiosa)  canaliculata.  In  this  species  the  cartilage  fossette 
is  the  same  as  in  Mactra  ;  the  marginal  teeth  are  feeble,  and  there  are  no 
laterals.  The  shells  of  Mactra  which  we  have  examined  are  heavy  or  at 
least  solid,  hut  BfBta  is  thin  and  fragile  ;  it  is  pure  white  in  color  and  is 
gracefully  ornamented  by  concentric  raised  ribs.  The  shell  is  inflated 
and  gapes  slightly  posteriorly  ;  it  is  shining  white  within  and  is  deeply 
grooved  concentrically  in  accordance  with  the  external  ribs.  Length  two 
and  a  half,  height  two  inches.  From  Hatteras  to  Mexico,  this  is  one  of 
the  commoner  beach  shells,  but  since,  as  in  some  other  species  already 
named,  the  hinge  ligament  and  teeth  are  feeble,  the  valves  become 
separated  by  the  buffeting  of  the  waves,  and  are  cast  disjointed  and 
singly  upon  the  beaches.     (Plate  LXXXI.) 

Family  veneridje 

In  many  respects  this  is  the  most  distingnishedpelecypod  fam- 
ily. It  is  the  largest  in  number  of  genera  and  species,  is  of 
world-wide  distribution,  and  supplies  to  hungry  man  a  number 


448  MARINE  INVERTEBRATES 

of  comestible  species.  Several  of  its  genera  have  been  named 
after  various  goddesses  and  nymplis  on  account  of  the  great 
beauty  of  their  shells.  But  from  a  purely  biological  point  of 
view  also  the  VeneridcB  have  claims  to  distinction,  for  they  seem 
to  represent  about  the  highest  type  of  shell-development  among 
the  bivalves.  The  test  is  extremely  hard  and  often  porcelanous. 
It  is  solid  without  being  ponderous  and  unwieldy  in  the  sense  of 
causing  the  animal  to  be  helplessly  overburdened  by  the  sheer 
weight  of  its  shell.  The  valves  are  equal  and  have  three 
stout  cardinal  teeth.  The  foot  is  strong,  the  animal  is  active, 
the  siphons  are  free  or  partially  united,  and  the  gills  are  more  or 
less  crumpled  and  folded.  There  is  a  compactness  and  well-regu- 
lated arrangement  of  the  organs  in  the  Yeiieridce,  which  impress 
one  who  has  examined  the  anatomy  of  many  pelecypods  much 
as  a  well-built,  ef&cient,  and  space-economizing  machine  would 
impress  a  mechanic.  None  of  the  organs  are  weak  or  crowded 
out  to  furnish  room  for  the  undue  or  awkward  development  of 
other  organs.  A  good  balance  is  preserved  between  them  all, 
the  result  being  a  high  type  of  pelecypod. 

If  we  do  not  expect  to  find  any  of  the  more  remarkable  forms 
of  the  VeneridcB  upon  our  shores  we  shall  be  the  less  disappointed 
when  returning  from  collecting-expeditions.  Nevertheless,  there 
are  a  few  species  of  CytJierea,  Dosinia,  and  Tivela  in  North  Ameri- 
can waters  which  are  very  handsome  shells  ]  but  those  of  our 
species  which  are  included  under  the  generic  name  Venus  are  in 
point  of  beauty  not  worthy  of  their  promising  name. 

Genus  Vemis 

V,  Tnercenaria,  This  is  the  common  '^  hard-shell  clam,"  the  "  Lit- 
tle Neck  "  of  the  hotels  and  restaurants,  with  which  every  one  in  New  York 
and  New  England  is  familiar.  The  species  ranges  from  Cape  Cod  to 
Florida,  and  occupies  two  different  kinds  of  station :  one  in  shallow 
muddy  bays  near  low-tide  mark,  in  estuaries,  etc. ;  the  other  the  sandy 
stations  in  open  deeper  bays  or  the  open  ocean.  Those  coming  from 
"  outside  "  have  thinner,  more  delicate  shells,  with  thin,  concentric  ribs. 
They  burrow  in  the  sand  or  mud,  or  crawl  quite  rapidly.  The  siphons 
are  short  and  are  united  almost  to  their  ends.  The  mantle  is  open  (save 
for  the  siphons),  and  the  edges  are  delicately  frilled.  In  the  United 
States  this  species  is  very  extensively  gathered  for  the  markets.  When 
the  oyster  season  closes  in  April,  the  hard-shell  clam  comes  into  vogue, 
the  season  lasting  until  September  or  October.     The  clams  are  exten- 


PELECYPODS 


449 


sively  gathered  in  the  estuaries  from  Gape  May  to  Cape  Cod.  Men 
armed  with  rakes  drift  about  in  small  boats  and  fish  the  sluggish  crea- 
tures up  out  of  the  mud.  They  will  live  for  many  days  out  of  water  if 
kept  in  a  cool  place.  Smaller  or  immature  clams  are  better  for  the  table, 
since  they  are  not  so  tough  as  their  elders.  A  few  features  of  the  shell 
of  this  species  are  noticeable — the  rather  prominent  umbones  directed  for- 
ward^ the  heart-shaped  lunule,the  external  ligament,  the  concentric  sculp- 
turing of  growth -lines,  the  pure-white  interior  (with  occasionally  violet 
zones  about  the 
muscle-scars  and 
margin),  the  three 
stout  cardinal  teeth, 
the  sharp -angled 
pallia!  sinus,  and  the 
ventral  margin  fine- 
ly crenulated  within. 
The  greatest  length 
is  about  three  inches 
and  the  height  two 
and  a  half  inches, 
but  these  dimensions 
exceed  those  of  the 
clams  usually  served 
upon  the  half -shell. 
V.  mercenaria  ranges 
into  Florida,  increas- 
ing in  size  and  bulk 
as  it  meets  the 
warmer  waters  of 
the^ulf  Stream.  The 
Floridian  form  has  received  the  Varietal  name  of  mortoni.  This  massive 
clam  sometimes  weighs  five  pounds,  and  is  fully  six  inches  in  diameter. 
Aside  from  its  great  size  and  thickness,  the  characters  of  the 
shell  are  wholly  those  of  the  smaller  Northern  form.  It  is  abundant  in 
shallow,  muddy,  brackish  bays,  and  is  gathered  by  men  who  ^'  tread 
out "  the  clams,  feeling  for  them  in  the  mud  and  sand  with  bare  feet. 
The  flesh  is  tough  and  disagreeably  strong,  yet  the  natives  appear  to 
rehsh  it,  especially  when  it  is  made  into  a  chowder. 

V.  cancellata.  The  most  abundant  species  of  Venus  in  Florida, 
particularly  near  Tampa  and  on  the  west  side.  It  preserves  all  the 
characteristics  of  the  genus,  and  is  decorated  with  a  series  of  high, 
narrow,  concentric  ridges,  between  which  are  much  smaller  and  more 
numerous  radiating  riblets.  The  color  is  dirty  white  to  light  yellow- 
brown  without,  and  white  and  violet  within.  There  are  three  cardi- 
nal teeth  and  no  laterals.  The  lunule  is  heart-shaped;  the  pos- 
terior margin  is  broadened  into  a  wide,  concave  area  into  which  the 
concentric  ridges  do  not  pass.  Length  one  to  one  and  a  fourth  inches ; 
height  the  same.  Sometimes  the  beaches  in  Florida  will  in  places  be 
banked  up  with  the  valves  of  this  very  abundant  Venus.  As  they  live  in 
shallow  water  upon  sandy  stations,  they  are  easily  dislodged  by  the 
heavy  storms  which  sometimes  sweep  that  usually  placid  coast.      (Plate 

29 


Venus  mercenaria,  typical  form. 


450  MARINE  INVERTEBRATES 

Genus  Cytherea 

C.  (Callista)  gigantea.  One  of  the  most  beautiful  Floridian  shells. 
It  is  nearly  or  quite  six  inches  long  and  about  three  and  a  fourth  inches 
in  height.  The  shell  is  porcelanous,  is  covered  with  a  pinkish,  livid 
epidermis,  and  is  decorated  with  numerous  longitudinal  color-rays  of 
lilac.  The  rays  are  usually  broken  and  interrupted.  Within  it  is  china- 
white,  and  has  a  deep  palhal  sinus.  It  is  very  abundant  on  the  west 
coast  of  Florida,  at  Sanibel  Island,  Egmont  Key,  Lake  Worth,  and  on 
beaches.     (Plate  LXXXII.) 

C,  maculata.  This  species  is  more  oval  in  outhne  than  the  last.  It 
is  of  a  fawn-color,  blotched  or  waved  with  violet-brown,  and  is  porcela- 
nous  and  shining.  The  epidermis  is  also  shining  and  corneous.  Within 
it  is  china-white  in  color.  The  palhal  sinus  is  very  deep  and  wide. 
Length  two  and  a  half  to  three  inches ;  height  one  and  a  half  to  two 
inches.  This  also  is  a  shell  to  be  looked  for  upon  the  beach  after  storms, 
but  it  will  probably  not  be  seen  on  the  east  coast  of  Florida,  although  it 
occurs  on  the  Keys  and  also  at  Hatteras.  Both  of  the  species  have  been 
used  as  food,  but  not  very  extensively.  The  flesh  is  not  lacking  in  ten- 
derness, but  it  has  a  peppery  taste.     (Plate  LXXXII.) 

Genus  Dosinia 

There  are  two  species  of  this  very  graceful  genus  of  Veneridce  south  of 
Hatteras,  X>.  discus  and  X>.  elegans.  These  dosinias  have  united 
siphons.  The  foot  is  very  large  and  strong,  and  the  mantle  margin  is 
both  papiUaceous  and  plicated.  The  shells  of  these  two  species  are 
about  three  or  three  and  a  half  inches  in  length  and  of  the  same  height, 
and  are  very  flat.  The  ventral  margin  is  almost  a  perfect  circle,  and  the 
beaks  are  small  and  pointed.  The  lunule  is  small  and  cordate ;  the  valves 
are  very  gracefully  sculpturedin  fine,  regular,  impressed,  concentric  striae, 
which  are  finer  and  less  elevated  in  B.  discus  than  in  JD.  elegans;  the  shell 
is  porcelanous  and  white,  and  is  covered  by  a  straw-colored,  very  fine, 
transparent  epidermis.  Within,  the  strong  cardinal  teeth  are  placed 
upon  a  long  fossette.  There  is  a  deep  pallial  sinus.  B.  discus  is  charac- 
teristic of  the  east  coast  of  Florida,  while  D.  elegans  is  only  found  upon 
the  west  side  of  the  State.  Both  may  be  looked  for  upon  the  beach, 
though  hving  specimens  must  be  captured  with  the  dredge.  (Plate 
LXXXII.) 

Genus  Tivela 

The  coast  of  California  is  also  favored  by  the  Yeneridm,  a  num- 
ber of  large  species  belonging  to  several  genera  being  present. 

T.  crassatelloides.  Perhaps  the  largest  and  finest  of  the  California 
species.  It  is  so  common  in  its  between-tides  station  that  it  used  to^  be 
collected  by  plowing  a  furrow  through  the  sand,  the  big  shells  being 
thrown  out  upon  either  side  like  potatoes.  The  shells  attain  a 
length  of  five  and  a  half  inches,  and  are  porcelanous,  thick,  and 
heavy.  The  margins  of  the  valves  are  also  thick  and  rounded.  The 
exterior  is  perfectly  smooth,  yellowish-white  in  color,   and  decorated 


PLATE   LXXXII. 


Venus  cancellata. 

Cytherea  (Callista)  maculata. 


Cytherea  (Callista)  gigantea. 
Dosinia  discus. 


PLATE   LXXXIII. 


Tivela  crassatelloides,  one  half  natural        Tapes  laciniata,  one  half  natural  size. 

size.  •  Chione  simillima. 

Chione  suceincta. 


PELECYPODS  451 

with  purplish  rays  arranged  in  various  groupings ;  over  all  is  a  glossy- 
epidermis.  The  hinge-teeth  are  very  strong,  and  a  prominent  anterior 
lateral  tooth  on  the  left  valve  is  noticeable.  There  is  an  external  Hga- 
ment;  the  pallial  sinus  is  well  marked,  but  not  very  deep.  (Plate 
LXXXIII.) 

Genus  Chione  " 

There  are  three  species  on  the  west  coast.  This  genus  is 
very  closely  allied  to  Venus,  and  is  considered  by  many  to  be 
only  a  subgenus  of  the  latter.  All  three  species  are  white,  solid, 
heavy  shells  which  exhibit  the  same  scheme  of  sculpturing, 
namely,  numerous  longitudinal  ribs  crossed  by  larger  and  less 
frequent  concentric  ridges. 

C.  simillima  is  shaped  almost  exactly  Uke  the  east-coast  Venus  can- 
cellata,  but  its  concentric  ridges  are  very  numerous  and  sharp.  There  is 
a  strongly  marked  cordate  lunule,  and  hardly  any  pallial  sinus.  Length 
one  and  a  half  to  two  inches.     (Plate  LXXXIII.) 

C  succincta  has  fewer  concentric  ridges  and  has  a  large  lunule. 
There  are  purple  zones  within  and  touching  the  heavy  cardinal  teeth. 
Length  two  and  a  half  inches.     (Plate  LXXXIII.) 

C.  fiuctifraga  has  broad  but  flatter  or  well-rounded  (not  sharp)  con- 
centric ridges,  no  lunule,  a  small  hgament,  a  fairly  deep  pallial  sinus, 
and  a  finely  crenulated  margin  (within)  all  around  the  valves,  except 
when  interrupted  by  the  hinge  ligament.  The  shell  is  solid  and  shining, 
and  marked  by  deep-purple  zones  within.  Length  one  to  two  inches. 
Found  in  southern  California. 

Genus  Tapes 

This  is  a  prominent  genus  of  the  Veneridm.     Its  chief  feature 

is  the  total  want  of  lateral  teeth.     There  are  several  large  species 

in  California. 

T.  staminea,  T.  lacinicita.  These  are  the  most  noticeable  species. 
The  former  is  sold  in  the  San  Francisco  markets  as  the  "'  hard-shell  clam." 
The  shell  of  this  species  is  from  two  to  three  inches  in  length  and  of 
somewhat  less  height,  rounded,  and  heavy.  The  sculpturing  consists  of 
radiating  ribs  traversed  by  strongly  marked  growth-lines.  The  teeth 
are  strong,  and  the  paUial  sinus  is  deep.  T.  lacinicita  is  much  like  the  last, 
but  its  surface  is  reticulated  by  a  crisscross  design  that  is  very  striking. 
It  also  has  a  deep  pallial  sinus.  These  two  species  are  of  Southern  range. 
They  burrow  in  gravelly  places,  among  stones,  between  tide-marks,  and 
their  presence  may  frequently  be  detected  when  walking  along  the  beach 
at  low  tide  by  seeing  a  sudden  jet  of  water  ejected  from  a  little  hole  in 
the  mud  or  gravel.  The  animal,  becoming  alarmed  at  the  approach  of 
something,  suddenly  snaps  shut  its  valves,  and  thus  forces  out  some 
water  through  its  siphons.  The  foot  is  very  strong  and  often  byssifer- 
ous  in  this  genus.    (Plate  LXXXIII.) 


452 


MARINE   INVERTEBRATES 


G-ENus  Saxidomus 

S.  nuttalUL  The  last  of  the  larger  west-coast  Veneridce  which  we 
shall  examine.  The  genus  is  very  closely  allied  to  Tapes,  and  no  doubt 
might  better  be  considered  as  its  subgenus.  The  shell  is  brownish- 
white,  three  to  four  inches  in  length,  and  heavy,  rough,  and  coarse-look- 
ing, with  irregular  concentric  ridges.  There  is  no  lunule,  but  a  large 
external  ligament  is  very  prominent  just  back  of  the  beaks.  Within  it 
is  white,  with  a  deep  paUial  sinus.  Just  below  the  ligament  area  is  a 
zone  of  translucent,  agate-like  shell-structure.  This  large  clam,  with 
several  others  of  the  same  genus,  lives  in  shallow  water  near  shore. 

Family  peteicolid^ 

Genus  I^etricola 

J*,  pholadiformis.  Along  the  Jersey  coast,  especially  about  Atlantic 
City,  there  are  small  patches  of  clay  or  hard  tenacious  mud  which  lie 
just  at  the  edge  of  the  sea.  As  the  beating  of  the  surf  gradually 
encroaches  upon  these  hard  fragments  of  once  extensive  clay-beds,  many 
specimens  of  this  curious  bivalve  mollusk  are  washed 
out  from  their  burrows  in  this  clay  and  cast  upon  the 
sandy  beach.  The  animal  has  long  siphons  which  are 
united  about  one  third  of  the  way  to  their  ends.  Al- 
though this  creature  is  alhed  to  the  Veneridce,  the  degree 
of  mantle  fusion  present  is  much  greater,  leaving  in  this 
case  only  a  fairly  long  slit  through  which  the  foot  may 
protrude.  The  shell  is  very  dissimilar  to  that  of  any  of 
the  Veneridce,  and  in  many  respects,  judging  from  a 
conventional  standard,  is  a  remarkable  form.  It  is  ex- 
ceedingly thin,  is  of  a  chalky  texture,  gapes  widely  pos- 
teriorly, and  is  ornamented  with  transverse  ribs,  which 
are  feeble  upon  the  long  produced  posterior  portion  of 
the  shell,  but  strong  in  the  anterior  part,  where  they  are 
crossed  by  the  coarse  lines  of  growth,  which  appear  like 
vaulted  scales  upon  the  ribs.  The  color  is  a  dull  white. 
There  are  two  cardinals  in  each  valve  and  no  laterals. 
Length  one  and  a  quarter  to  two  and  a  half  inches ; 
height  one  half  to  three  quarters  of  an  inch.  This 
species  passes  its  entire  life  in  the  burrow  it  has  made 
for  itself  in  the  clay.  Its  only  motions  are  made  in  climbing  to  the  en- 
trance of  its  burrow  or  in  retreating  far  out  of  sight  within  its  depths. 
Its  siphons  are  tipped  with  a  dark  or  drab  color  as  a  measure  of  protection 
from  the  predaceous  crabs  which  range  about  the  mud  surfaces  near 
tidal  marks,  and  are  always  upon  the  lookout  for  succulent  bits  of  flesh. 
J*,  carditoides.  A  petricola  of  the  Calif  ornian  coast,  very  similar  in  its 
habits  to  the  east-coast  form.  It  bores,  however,  not  only  into  clay,  but 
also  into  soft  rocks  in  order  to  effect  a  permanent  lodgment.  Often  this 
species  occupies  a  hole  which  it  has  discovered  already  existing ;  in  this 
case  its  shell  grows  to  fit  the  surroundings.  The  hinge-teeth  and  sculp- 
turing are  frequently  reduced  and  sometimes  are  quite  obsolete ;  but 
the  shell  has  the  chalky,  thin  texture  that  is  characteristic  of  the  genus. 


Petricola  pholadi- 

formis. 


PELECYPODS  453 

There  is  another  family  of  rock-  and  mud-boring  bivalves  which 
superficially  resemble  the  petricolas,  but  their  anatomical  organization 
removes  them  to  a  little  distance  from  the  Petricolid^.  They  are  con- 
sidered further  on,  under  the  name  of  Pholadidce. 

FAIVnLY  CARDIIDiE 

•Genus  Cardium 

This  is  another  important  family  of  the  Pelecypoda,  which, 
vith  the  Veneridce,  the  JfactridcB,  and  the  TeUimdce-,  is  entitled  to 
distinction  on  account  of  its  high  organization,  its  high  type  of 
shell,  its  universal  geographical  distribution,  and  its  great  beauty. 
The  dominant  genus  is  Cardium — a  name  given  on  account  of  the 
fact  that  the  shell  is  shaped  like  a  heart.  The  animal  has  a  very  long, 
recurved,  and  surprisingly  strong  foot.  The  mantle-edges  are  quite 
freely  open  to  the  siphonal  region  and  are  highly  papillate  and 
waved.  The  siphons  are  usually  very  short,  but  have  wide  exterior 
openings  and  are  also  strongly  papillate  about  their  margins. 
The  gills  are  obliquely  situated,  and  seem  to-be  thicker  and  heavier 
than  is  usual  in  pelecypods;  they  are  much  folded,  the  outer 
lamella  being  the  smaller.  With  such  a  pointed  foot  and  such 
short  siphons  Cardium  is  obviously  not  a  deep-burrowing  genus ; 
but  it  does  partially  bury  itself  in  soft  semi-liquid  sand.  Its  pro- 
gression is  effected  by  leaps  which  it  is  enabled  to  make  by  reach- 
ing far  out  with  its  foot,  then  suddenly  twisting  to  one  side  and 
thi'owing  the  shell  several  inches.  The  shell  is  ventricose,  is 
closed  or  gapes  slightly  posteriorly,  and  has  prominent  subcentral 
umbones  and  an  external  ligament.  The  sculpture-scheme  of 
Cardium  (if  the  shell  is  not  perfectly  smooth)  is  one  of  radiating 
ribs  or  ridges,  which,  being  regular,  form  a  perfect  crenulation  of 
the  ventral  margin.  There  are  two  cardinal  teeth  in  the  center, 
and  one  lateral  tooth  upon  both  the  anterior  and  the  posterior  side  : 
the  latter  are  situated  at  some  little  distance  from  the  beaks. 

C  mcignum.  The  largest  and  finest  '^cockle "  of  the  east  coast  of  the 
United  States.  It  is,  indeed,  one  of  the  finest  cockles  in  the  world.  The 
almost  perfect  heart-shape  is  striking.  The  posterior  side  is  some- 
what flatly  depressed.  The  thirty-three  to  thirty-seven  regularly  dis- 
posed, broad,  radiating  ribs  ;  the  regularly  crenulated  margins ;  the 
yellowish-brown  color  garnished  with  transverse  rows  of  chestnut  or 


454  MARINE  INVERTEBRATES 

purple  lines  or  spots  ;  the  brownish-purple  posterior  area — all  combine 
to  make  this  large  Cardium  a  beautiful  species.  Its  length  is  four  inches; 
height  five  and  a  quarter  inches.  It  is  a  very  abundant  species  on  the 
open  Florida  beaches,  where  it  is  often  left  exposed  and  alive  at  very 
low  tides.     (Plate  LXXXIV.) 

C.  isocardia.  This  also  is  a  Floridian  species,  of  elongated  heart- 
shape  and  with  radiating  ribs.  It  is  not  more  than  half  as  large  as  the 
last- described  species.  The  ribs  are  decorated  with  erect  vaulting  scales 
which  are  exaggerated  portions  of  growth-lines.  The  beaks  are  smaller 
in  proportion  than  in  C.  magnum.  The  shell  is  brown  to  straw-color, 
stained  with  purplish-brown  without,  and  has  a  bright  salmon -red  or 
purplish-pink  interior.  The  margins  are  deeply  crenulated.  The  teeth 
are  arranged  as  in  the  last-described  species.  It  is  very  common  on  the 
beaches  of  western  Florida.    (Plate  LXXXIV.) 

C,  serratunif  C,  Icevigatum,  These  two  species  have  a  perfectly 
smooth  surface,  and  inflated,  globose,  heart-shaped  shells,  and  are  of  a 
creamy-white  color,  suffused  with  a  yellowish,  golden  tint  which  suggests 
the  color  of  butter.  Some  forms  are  shiny,  and  citron-yellow  and  pinkish 
toward  the  margins,  whence  the  name  of  ''  peach-shell."  Height  one  to 
two  inches.  Not  uncommon  upon  Florida  beaches.  (Plate  LXXXIV.) 
C  mortoni.  Another  of  the  smooth  forms  of  Cardium  (placed  in  the 
subgenus  Lcevicardium).  It  occurs  in  Florida  and  also  extends  up  the 
coast  to  Cape  Cod,  being  very  abundant  in  Long  Island  Sound.      In 

the  neighborhood  of  Martha's  Vineyard  and  along 
the  north  shore  of  Long  Island  this  very  pretty 
little  species  has  been  reported  as  occurring  in  soft 
ground  even  above  low-tide  mark,  near  the  mouths 
of  creeks.  It  is  enough  to  say  of  it  that  it  is  a 
smaller  edition  of  C.  Icevigatum  and  may  be  further 
distinguished  by  a  purple  blotch  on  the  posterior 
margin,  just  within  the  valves,  the  general  color 
within  being  bright  yellow.     In  young  specimens, 

Cardium  mortoni,  showing  zigZag  liueS  of  dark  fawn-COlor  upon  the  pale- 
extended  animal.  yellowisli  background  of  the  smooth  exterior  sur- 
face of  the  shells  are  a  noticeable  feature.  The  largest  specimens  mea- 
sure an  inch  in  length  and  nearly  the  same  in  height.  The  long  cirri 
upon  the  siphons  are  striking. 

C.  substriatum,  A  cockle  of  this  inflated,  smooth  type,  which 
strongly  resembles  the  east-coast  form,  found  upon  the  Pacific  coast. 
The  name  indicates  that  it  is  not  altogether  smooth,  a  fact  only  revealed, 
however,  by  a  magnifjdng-glass.  It  is  about  one  half  of  an  inch  in 
length,  and  of  a  light  drab-color,  spotted  and  sometimes  radially  lined 
with  yellowish-brown.  Professor  Keep  likens  this  species  in  both  shape 
and  color  to  a  sparrow's  egg.     (Plate  LXXXIV.) 

C,  elatufn,  A  veritable  giant  among  the  cardium  s.  It  is  found  on 
the  southern  Californian  coast,  though  rarely  north  of  the  Mexican 
border.  It  is  of  the  smooth,  glossy  type  belonging  to  the  subgenus 
Lcevicardium.  It  attains  a  diameter  of  six  inches,  and  is  of  a  creamy- 
yellow  appearance. 

C.  corbis,  C  qiiadrigenarium.  These  two  Californian  cockles  are 
of  the  ribbed  type  displayed  in  the  eastern  C.  magnum  and  C.  isocardia. 
C.  corbis  is  found  in  the  northern  Californian  and  Puget  Sound  region, 


PLATE   LXXXIV. 


1,  Cardiura  magnxim,  much  reduced. 

2,  Cardium  isocai'dia. 

3,  Cardium  Isevigatum. 


4,  Cardium  substriatum,  enlarged. 

5,  Cardium  corbis  (young  specimen). 
6   Glvcimeris  generosa. 


PELECYPODS 


455 


and  C.  quadrigenarium  on  the  southern  shores  of  California.  The  former 
is  a  full,  round,  heart-shaped  shell  with  about  thirty  somewhat  scaly- 
ribs.  The  edge  of  the  shell  is  deeply  toothed;  the  color  hght  brown- 
ish ;  the  diameter  from  two  to  three  inches.  It  preserves  all  the  features 
of  the  genus  as  regards  both  shell  and  anatomical  characters.  The  other 
species,  C.  quadrigenarium,  very  strongly  resembles  C.  magnum  in  size 
and  shape.  It  lacks 
the  flattened  area  on 
the  posterior  portion 
of  the  shell  which  is 
characteristic  of  the 
east-coast  species,  and 
its  uniform  brownish - 
white  coloration  is  less 
striking.  It  has  about 
forty  regularly  spaced, 
radiating  ribs,  which 
are  smooth  upon  the 
umbonal  region,  but 
elsewhere  are  armed 
with  spiny  processes. 
Diameter  about  six  in- 
ches. (PlateLXXXIV. ) 
C,  islandicuin,  C, 
piTiniilatiim,  Both 
of  these  are  cold-water 
species  and  occur  along 
the  New  England  coast. 
The  former  has  a  shell  cardium  isiancucum. 

which  varies  from  one  half  of  an  inch  to  two  inches  in  length,  and  has  from 
thirty-six  to  thirty-eight  sharp,  three-sided,  radiating  ribs,  the  furrows 
between  them  being  rounded  and  wrinkled  by  growth-lines.  A  yellow- 
ish-brown epidermis  covers  the  shell  and  bristles  into  a  sort  of  fringe  upon 
the  sharp  edges  of  the  ribs.  C.  islandicum  cannot  be  said  to  be  a  very 
common  species  in  New  England,  although  collectors  have  so  reported  it. 
Specimens  from  Massachusetts  are  not  as  large  as  those  of  more  northern 
habitat.  It  does  not  occur  south  of  Cape  Cod.  C.  pinnulatum  is  one  of  the 
''small  fry"  among  the  cockles.  Its  largest  diameter  is  less  than  one 
half  of  an  inch ;  but  what  it  lacks  in  size  it  seems  to  endeavor  to  make 
up  in  abundance,  for  it  is  scattered  everywhere  along  the 
coast  from  New  York  northward.  Specimens  can  nearly 
always  be  found  in  the  stomachs  of  fishes,  which,  by  the  way, 
form  an  excellent  hunting-ground  for  rare  species  of  mol- 
lusks  of  small  size.  There  are  twenty-six  shghtly  rounded 
ribs,  with  deep  linear  grooves  between  them.  Upon  the  ribs, 
especially  in  the  posterior  portion  of  the  shell,  are  arched 
scales,  folded  so  as  to  appear  like  blunt  spines.  The  species 
may  easily  be  distinguished  from  the  young  of  C.  islandicum  by  the 
smaller  number  of  ribs.  The  animal,  C.  pinnulatum,  is  said  to  be  exceed- 
ingly lively  and  able  to  make  rapid  progress  over  gravelly  bottom  by  exe- 
cuting sudden  leaps.  It  has  a  long,  recurved,  very  strong  foot,  and  its 
movements  are  effected  as  described  above.   It  is  abundant  at  Bar  Harbor. 


456 


MARINE   INVERTEBRATES 


Family  myid^ 


Genus  Mya 

In  this  family  we  encounter,  rather  suddenly,  some  new  fea- 
tures not  heretofore  seen  in  the  pelecypod  structure.  In  the 
first  place,  the  siphons  are  enormously  large,  are  united,  and  are 
surrounded  by  a  leathery  epidermis.  The  mantle-edges  are  fused 
together  along  the  entire  ventral  margin,  except  for  a  small  slit 
through  which  the  foot  may  project.  Although  the  animal  may 
withdraw  the  long  siphons  into  its  shell,  yet  they  remain  to  a 
certain  extent  exposed,  for  the  valves  gape  widely  posteriorly, 
and  only  slightly  less  so  anteriorly.  In  the  economy  of  these 
forms  the  shell  seems  to  play  a  less  important  part  than  it  does 
in  the  Veneridce,  in  the  Tellinidm,  and  generally  in  those  families 
whose  shells  are  strong  and,  closing  firmly,  afford  the  animal 
within  a  real  protection.  The  sheU  of  Mya  (the  principal  genus) 
is  thin,  white,  and  of  a  softer  chalky  texture ;  it  gapes  widely 
^^  fore  and  aft,"  and  has  a  loosely  constructed  hinge  apparatus, 
consisting  of  an  erect  projecting  tooth,  which  fits  into  a  pit  in 
the  opposite  valve. 

M,  arenaria.  TJiis  is  the  common  '^  soft-shell  clam"  of  New  Eng- 
land. Its  range  is  from  Cape  Cod  to  Greenland  and  Great  Britain. 
Upon  the  Maine  coast  it  is  very  extensively  gathered  and  sold  to  the  Banks 
fishermen  for  bait.  Its  use  as  food  for  man  is  probably  not  very  great, 
yet  it  is  always  to  be  seen  on  sale  in  the  markets  of  New  England  coast 
towns.  It  cannot  compare  in  flavor  with  Venus  mercenaria,  the  ''hard- 
shell clam"  south  of   Cape  Cod.     M.  arenaria  fives  between  tides  in 

muddy,  sandy,  peb- 
bly, or  even  rocky 
ground,  where  it 
can  find  material  in 
which  it  can  burrow 
and  hide  itself.  It 
hes  just  below  the 
surface,  with  its  si- 
phons projected  into 

<$^^&=^=^_^b^^^^^^^^e?^^5^-,^,j/     ^^®   water.       When 
\  ^<r---^^s;^s^===a=^^===.s=?-=5^  --..i^-AmfJ/      ^^g    water   recedes, 

Mya  draws  in  its  si- 
phons and  awaits  the 
return  of   the   tide, 
Mya  arenaria.  cvcry  now  and  then 


PELECYPODS 


457 


ejecting  a  jet  of  water  into  the  air.  The  shells  vary  considerably  in  size 
and  thickness  of  valves.  Large  specimens  are  three  and  a  half  inches  long 
and  two  inches  high.  Our  forefathers  were  not  always  well  posted  upon 
the  habits  of  mollusks,  even  though  they  may  have  relished  them  in 


Mya  arenaria,  showing  extended  animal. 


chowders  and  believed  their  flesh,  to  possess  valuable  cui'ative  proper- 
ties. John  Winthrop,  iu  1634,  gave  a  list  of  useful  American  animals, 
in  which,  he  remarked  :  '^  Clam,  white ;  their  broth  is  most  excellent  in 
all  intermitting  fevers,  consumption,  etc.  These  clams  feed  only  on 
sand."     What  marvelous  digestive  powers ! 


Family  solenid^ 
In  this  family  are  included  the  long,  slender  bivalves  com- 
monly known  as  ^^  razor-shells."  Every  one  who  has  been  to  the 
sea-shore  has  become  familiar  with  these  odd-looking  mollusks, 
for  their  valves  are  always  to  be  found  upon  every  beach.  Their 
station  is  upon  sandy  flats  or  bars  more  or  less  exposed  at  low 
tide.  They  burrow  into  the  sand  perpendicularly  to  a  depth  of 
two  or  three  feet,  remaining  hidden  most  of  the  time.  Occasion- 
ally a  colony  of  them  will  be  seen,  each  one  projecting  slightly 
from  his  burrow.  If  approached  most  cautiously  some  of  them 
may  be  captured,  but  if  the  sand  is  jarred  they  all  take  fright 
and  disappear  in  an  instant.  It  is  no  easy  matter  to  capture  a 
'^ razor"  when  once  he  has  taken  warning,  for  he  will  dig  down 
into  the  sand  about  as  fast  as  one  can  follow  with  a  spade.     A 


Ensis  clirectus,  showing  extended  animal:  1,  foot ;  2,  siphons  ;  3,  papillae,  enlarged. 


good  way  to   catch    one   is  to  approach  his  burrow  carefully, 
and  then  plunge  a  spade  obliquely  down  below  him,  thereby 


458 


MARINE  INVERTEBRATES 


cutting  off  Ms  retreat.  So  tenaciously  will  they  cling  to  the  sand 
by  expanding  the  muscular  foot  that  the  shell  may  be  puUed  en- 
tirely off  the  body  before  they  will  let  go. 

G-ENUs  Ensis 

E,  directus  (Solen  ensis,  JEnsis  americanus). 

The  common  species  upon  the  New  England  and 
Jersey  coasts.  The  foot  is  long,  and  protrudes  from 
one  end  of  the  long  shelly  it  is  also  very  strong, 
and  capable  of  change  at  will  into  almost  any  form, 
from  a  pointed  bulb  to  a  flat  disk.  The  siphons, 
which  project  from  the  opposite  end  of  the  shell, 
are  short  and  are  not  united.  The  gills  are  long. 
The  juxtaposition  of  these  organs  is  at  first  con- 
fusing, because  the  greatly  elongated  form  of  the 
shell  and  the  habits  of  the  animal  in  burrowing 
vertically  into  the  sand  have  caused  the  foot  to  be 
pushed  farther  away  from  the  posterior  portion  of 
the  shell  and  to  protrude  in  a  direction  just  opposite 
to  the  siphons.  The  shells  are  bent  or  slightly 
curved;  they  gape  at  both  ends;  and  they  are 
fitted  with  very  small  interlocking  teeth  at  the  up- 
per corner  of  the  posterior  end.  The  color  is  white, 
but  a  yellowish  or  greenish  glossy  epidermis  covers 
the  entire  test.  Length  about  six  inches.  The 
manner  in  which  the  animal  makes  its  rapid  de- 
scent into  the  sand  is  very  interesting.  First  ex- 
tending the  foot  lengthwise  into  a  point,  it  plunges 
it  into  the  sand ;  then,  by  forcing  water  into  the 
organ  it  expands  it,  thus  pushing  away  the  sand  on 
all  sides ;  and  still  further  expanding  the  foot  at  the 
end  into  a  disk,  it  secures  an  anchorage  which  en- 
ables it  to  draw  down  its  shell.  By  quick  repe- 
tition of  this  process  Ensis  can  get  out  of  sight  in 
a  remarkablv  sudden  manner. 


Genus  Solen 

S.  viridis,  A  smaller  species,  about  two  inches 
in  length,  and  with  a  nearly  straight  light-green 
shell.  It  is  often  abundant  from  New  Jersey  south- 
ward. 

Ensis  directus.  S,  slcavius.     The  commou  Calif  ornian  species  of 

Northern  range.  It  is  only  about  two  inches  long, 
and  is  rounded  anteriorly,  but  is  chopped  off  squarely  behind.  It  is 
slightly  curved  and  white,  and  has  a  glossy  brown  epidermis. 

S,  rosaceus.  Another  species  of  Southern  range,  very  similar  in  form 
to  the  last,  but  straighter  and  rosy-white  in  color.  The  epidermis  is 
glossy  brown.     Length  two  inches. 


PELECYPODS 


459 


Genus  Tagelus 

T,  gihhus.  The  extended  range  and  shore  station  of  this  exceedingly 
abundant  species  wUl  cause  it  to  be  among  the  first  accessions  to  the 
cabinet  of  the  collector  south  of  Cape  Cod.  It  burrows  deep  in  sand 
and  mud,  leaving  two  small  openings  to  the  hole  for  the  accommodation 


Tagelus  gibbus,  showing  extended  animal. 


of  its  two  excessively  long  siphons.  As  in  Solen  and  Ensis,  the  foot  is 
large  and  muscular,  tongue-shaped,  and  capable  of  remarkable  change 
of  form  and  great  freedom  of  movement.  The  long  white  siphons,  sepa- 
rated from  the  base  and  each  provided  with  orange-colored  eyes  (or, 
rather,  a  rudimentary  sort  of  visual  organs),  are  the  most  important 
feature.  The  apex  of  the  hinge  is  not,  as  in  Solen  and  Ensis,  at  the  end 
of  the  shell,  but  is  more  conventionally  placed  near  the  middle ;  the 
cardinal  teeth  are  very  small,  two  upon  each  valve  and  interlocking ; 
a  flat,  oblong,   callous  process  serves  as  a  fossette.     The  dorsal  and 

ventral  margins  are  parallel,  and 
gape  at  both  ends ;  the  shell  is  white, 
and  is  covered  with  a  dense  yellow- 
ish epidermis,  which,  passing  the 
ventral  margin,  appears  to  become 
continuous  with  the  thickened  man- 
tle-edge. There  is  no  other  species 
north  of  Hatteras  with  which  this 
could  be  confounded.  The  double  entrance  to  the  burrow,  which  may 
be  discovered  about  low-tide  mark,  is  unique.  T.  gibbus  is  a  good  spe- 
cies to  examine  for  the  crystalline  stylet  in  the  digestive  tract. 


Tagelus  gibbus. 


Family  GLYCiMEiiiD.ffi 


Genus  Glpcimeris 

6r.  generosa,  A  large  shell  of  the  Pacific  coast,  occurring  most 
abundantly  in  Puget  Sound  waters,  where  it  frequents  muddy  shallows. 
It  is  a  remarkable  pelecypod  in  respect  to  its  siphons  and  the  degree  of 
mantle  fusion.     The  appearance  of  the  animal  is  that  of  a  huge  pair  of 


460  MARINE  INVERTEBRATES 

united  siphons,  protected  laterally  at  theii*  larger  end  by  two  white, 
widely  gaping  valves.  The  very  small  pedal  opening  in  the  line. of 
mantle  juncture  indicates  a  very  small  foot.     (Plate  LXXXIV. ) 

Family  pholadid^ 

There  is  a  striking  resemblance  between  the  shells  of  this  rock- 
boring  family  and  those  of  the  petricolas— a  resemblance  which 
consists  principally  in  the  textnre  of  the  shell  and  the  tendency 
to  different  types  of  sculpturing  upon  the  posterior  and  anterior 
surfaces  of  the  valves. 

Genus  JPholas 

In  Fholas  the  anterior  part  of  the  hinge-margin  is  reflected 
back  oyer  the  umbones,  and  a  long  rib-like  tooth  springs  from 
under  the  umbonal  region  and  curves  out  almost  to  the  center  of 
the  valves.  The  shell  gapes  ''fore  and  aft,"  and  is  thin,  white, 
very  hard,  and  brittle.  The  animal  has  a  short,  truncated  foot 
and  a  small  orifice  in  the  mantle  through  which  the  foot  may  be 
projected.  The  siphons  are  long  and  are  united  almost  to  their 
ends.  Dorsally,  an  exposed  portion  of  the  animal  is  protected  by 
accessory  calcareous  plates.  The  habits  of  Fholas  are  very  inter- 
esting. It  is  found  in  holes  gouged  out  of  solid  rock  or  out  of 
pieces  of  wood ;  sometimes,  like  Petricola,  it  may  be  found  exca- 
vating in  hard  clay.  As  the  anterior  end  of  a  Fholas  shell  is  the 
larger  in  diameter,  and  is  the  end  which  is  most  deeply  buried  in 
the  rock  (the  opening  of  the  burrow  being  comparatively  small), 
there  was  some  mystery  as  to  the  way  in  which  the  creature  man- 
ages to  get  inside  its  rocky  dwelling.  Observations  in  aquaria 
have  shown  that  the  young  Fholas  begins  his  process  of  home- 
building  very  early  in  life.  The  wearing  away  of  the  stone  is 
effected  by  constantly  turning  the  shell  around,  scraping  with 
the  anterior  edges  of  the  valves.  A  lodging-place  having  been 
secured,  Fholas  is  obliged  to  work  constantly  to  enlarge  his  bur- 
row for  the  accommodation  of  his  growing  shell.  The  long  siphons 
may  project  from  the  hole  and  draw  in  food  and  breath,  but  the 
animal  is  a  prisoner  for  life.  When  Fholas  has  withdrawn  his 
long   siphons  he  is  reasonably  secure  from   his   enemies,  but 


PELECYPODS 


461 


nevertheless  thousands  of  them  are  destroyed  by  predatory  star- 
fishes, who  know  how  to  get  at  their  victims.  The  restless  crus- 
taceans, ever  on  the  outlook  for  a  meal, 
often  nip  the  siphons  of  the  rock-dwell- 
ers, and  a  kind  of  worm  sometimes 
attacks  them,  and,  destroying  the  ani- 
mal, proceeds  to  occupy  the  empty  shell 
and  burrow. 


F,  costata.  This  species  has  a  wide 
geographical  range,  being  found  from  Cape 
Cod  to  South  America,  but  it  is  not  abun- 
dant north  of  Hatteras.  In  Florida  it  bur- 
rows deep  in  sand  as  well  as  in  wood  or 
rock.  On  account  of  its  white  color  and 
suggestive  shape  and  sculpture,  it  has  re- 
ceived the  popular  name  of  ''angel's- 
wings."  It  grows  to  a  length  of  seven  or 
eight  inches. 

P.  t^mncata.  This  has  much  the  same 
range  as  the  last,  but  is  more  commonly  to 

be  found  in  New 
England  waters.  It 
also  bnrrows  in  any 
hard  substance,  or 
in  mud  above  low- 
water  mark.  It  is 
especially  common 
in  peat-banks. 

I*,  calif o^mica. 
A  Californian  Pho- 
las.  The  shell  is 
about  three  inches  in 
length,  and  resem- 
bles in  all  features 

and  habits  the  Pholas  of  the  east  coast.  Differ- 
ences in  the  shell  indicate  that  it  is  a  distinct 
species. 


Pholas  costata. 


Pholas  trmicata. 


Genus  Zirphwa 


Z.  cHspata,  A  species  of  Northern  range,  occurring  but  sparingly  in 
New  England,  in  hard  clay  or  rocky  burrows.  It  may  be  identified  at  once 
by  the  furrow  which  passes  from  the  beaks  across  the  valves  to  the  lower 
edges  of  the  shell  and  divides  the  surface  of  the  valve  into  two  areas. 
The  anterior  area  is  decorated  with  radiating  toothed  ribs ;  the  pos- 
terior area  is  smooth.     This  conchological  feature  of  the  genus  is  very 


462 


MARINE  INVERTEBRATES 


curious;  it  may  be  observed  also  in  several  deep-sea  genera  and  in  cer- 
tain extinct  fossil  forms.  The  length  of  this  shell  is  about  two  inches. 
This  species  also  occurs  in  California, 
where  its  favorite  station  is  in  hard  tena- 
cious clay.    Length  two  to  four  inches. 

Family  teredinid^ 


Genus  Teredo 


T,  navalis. 


Zirphcea  crispata. 


Teredo  navalis,  in  a  piece  of  tim- 
ber :  P,  pallets  ;  SS,  siphons  ; 
T,  tube ;  V,  valve  of  shell. 


This  species  is  worm- 
like in  form,  but 
it  has  a  small  bi- 
valve shell  at  the 
larger  end,  and 
near  the  anterior 
extremity  two 
calcareous  ap- 
pendages called 
pallets,  beyond 
which  extend  two 
siphons.  Along 
the  surface  of  the 
mantle  is  secret- 
ed a  continuous 
sheUy  tube  which 

lines  the  burrow.  This  mollusk,  commonly  called 
the  ''  ship-worm,"  is  exceedingly  destructive,  per- 
forating with  its  burrows  submerged  timber 
and  soon  rendering  it  useless.  Various  means 
are  taken  to  protect  ships,  the  piles  of  wharves, 
buoys,  and  the  like,  against  its  ravages ;  copper 
sheathing,  large-headed  nails  driven  close  to- 
gether into  the  wood,  verdigris  paint,  and  so 
on,  being  used  with  more  or  less  effect.  Vast 
numbers  of  these  animals  enter  the  wood  and 
burrow  in  various  directions,  but  they  never 
interfere  with  one  another,  a  thin  partition  of 
wood  always  being  left  between  adjacent  bur- 
rows. How  they  effect  the  burrowing  is  not 
determined,  but  it  is  supposed  to  be  by  means 
of  the  pallets.  Teredo  does  not,  like  the  boring 
isopod  Limnoria  lignorum,  feed  upon  the  wood. 
Its  food  consists  of  microscopic  organisms  which 
are  taken  in  through  the  incurrent  siphon.  In 
temperate  waters  T.  navalis  grows  sometimes  to 
the  length  of  six  inches ;  in  tropical  waters  it 
attains  the  length  of  two  feeto 

There  are  three  other  species  of  Teredo  and  one 
of  the  genus  Xylotrya  on  our  Northern  shores  -, 
T.  navalis  is,  however,  the  most  common  and 
most  destructive.  In  Southern  waters  there  are 
many  other  forms  of  these  boring  moUusks. 


PELECYPODS 


463 


Family  '^  pandorid^ 
Genus  Pandora 


P,  trilineata.  A  little  New  England  shell,  remarkable  on  account 
of  its  extreme  flatness.  When  looking  at  this  shell  before  opening  it, 
one  naturally  wonders  where  the  animal 
finds  room  to  exist  between  two  such 
disk-like  valves.  The  animal  is  very 
thin,  with  largely  united  mantle-edges, 
widely  separated  feeble  adductor  mus- 
cles, and  a  fairly  large  tongue-shaped 
foot.  The  shell  is  nacreous,  rounded 
anteriorly,  and  produced  posteriorly 
into  a  sort  of  upturned  tip  which  gapes 
to  accommodate  two  little  siphons.  The  dorsal  hinge-margin  is  excavated 
and  curved.  Length  about  one  inch.  It  is  abundant  at  Cape  Cod,  in 
sandy  stations,  on  oyster-beds,  and  is  found  from  Maine  to  Florida. 


Pandora  trilineata. 


TABLE  SHOWINa  THE   CLASSIFICATION  OF    THE    CEPHALOPODS 
DESCRIBED  IN  THIS  CHAPTEE 


/ 

CLASS 

CEPHALOPODA 

Subclasses 

Orders 

Genera 

Species 

Tetrabranchiata 

Nautilus 

Dibranchiata 

rOCTOPODA 

r  Octopus 
\  Argonauta 
/  Spirula 
J  Omrnastrephes 

A,  argo 

Idecafoda 

O,  illecehrosus 

\  Sepia                   , 
(  Loligo 

{ L.  Pealei 
(  L,  hrevis 

CLASS  CEPHALOPODA 

The  Cephalopoda  form  a  singularly  isolated  group,  and  are  so 
superior  in  organization  and  intelligence  to  all  other  mollusks 
that  it  is  difficult  to  believe  that  thej  are  first  cousins  to  the 
lethargic  gasteropod  and  the  simply  constructed  bivalve.  But 
the  class  bears  the  stamp  of  its  origin  in  a  mantle,  a  radula,  and 
a  disposition  of  internal  organs  and  functions  which,  although 
highly  perfected,  is  essentially  moUuscan. 

Along  the  Atlantic  coast  of  the  United  States,  particularly  in 
its  northern  portion,  occur  several  examples  of  cephalopods  be- 
longing to  the  genera  Ommastreplies  and  Loligo^  all  the  species  of 
which  are  referred  to,  in  common  parlance,  as  ''  squids."  They 
frequent  shallow  water,  and  are  often  to  be  found  in  weirs,  dart- 
ing about  with  rapid,  spasmodic  movements,  or  perhaps  lying 
motionless  on  the  bottom.  The  squids  enter  the  weirs  for  the 
purpose  of  capturing  the  young  mackerel  which  are  caught  in 
these  traps.  The  squid  lies  quietly  upon  the  bottom,  which  it 
simulates  so  closely  in  color  as  to  be  almost  invisible,  and  when 

464 


CEPHALOPODS  465 

a  school  of  fishes  swims  over  it,  darts  suddenly  into  the  midst  of 
it,  seizes  a  fish  with  its  sucker-bearing  arms,  and  kills  it  by  the 
bite  of  its  parrot-like  beak  or  jaws.  Sometimes  it  happens  that 
squids,  while  pursuing  fish  too  near  shore,  precipitate  themselves 
upon  the  beach,  where  they  flounder  about,  ejecting  water  from 
their  siphons,  which  pushes  them  only  farther  away  from  the 
water,  and  squirting  out  '''ink''  from  their  ink-sacs  in  a  vain  en- 
deavor to  hide  themselves  from  view.  On  bright  moonlight 
nights '-squids  often  go  ashore  in  vast  numbers,  and  perish  within 
a  few  inches  of  their  native  element,  which  they  seem  to  be  unable 
to  regain.  These  creatures  usually  swim  backward,  and  the  theory 
is  that,  dazzled  by  the  bright  light  of  the  moon,  they  continue  to 
gaze  at  it  while  swii^ming,  and  if  there  happens  to  be  a  shore  in 
the  direction  of  their  movements,  they  suddenly  find  themselves 
beached.  The  fishermen  of  Canada  and  New  England  take  advan- 
tage of  this  habit  and  capture  great  qua,ntities  of  squids  by  placing 
bright  lights  in  the  bows  of  their  boats  and  then  rowing  toward 
shore,  thus  driving  the  squids  out  of  the  water.  The  Banks 
fishermen  use  them  as  bait  for  catching  cod.  The  right  claimed  by 
American  fishing-schooners  to  purchase  squids  in  Newfoundland 
has  helped  to  keep  alive  the  quarrel  between  Canadian  and 
American  fishermen,  which  has  vexed  their  respective  govern- 
ments for  many  years. 

The  range  in  size  among  the  species  of  this  class  is  very  re- 
markable. The  little  sepiolas  are  about  an  inch  long ;  the  squids 
of  our  coasts  vary  in  length  from  eight  inches  to  one  foot ;  and 
the  giant  Architeuthis  of  the  North  Atlantic  measures,  often, 
fifty  feet  from  the  end  of  its  arms  to  the  tip  of  its  tail.  Such 
a  creature,  with  its  long  arms  pro\'ided  with  suckers,  its  power- 
ful jaws,  and  its  rapid,  alert  movements,  is  a  formidable  foe. 
These  animals  have  been  the  basis  of  many  legends  about 
sea-serpents  and  sea-monsters.  A  gruesome  story  of  an 
octopus  is  told  by  Victor  Hugo  in  "  The  Toilers  of  the  Sea," 
where  he  gives  a  thrillmg  account  of  a  man's  encounter  with 
a  devil-fish  in  a  cave.  One  who  has  read  this  tale  has  a  vivid 
picture  in  his  mind  of  the  giant  squid,  and  the  danger  of 
meeting  one  of  these  many-armed  foes.      Victor  Hugo's  devil- 

30 


466  MARINE  INVERTEBRATES 

fish,  however,  is  an  animal  not  true  to  nature,  but  a  composite^ 
having  the  attributes  of  the  polyp  and  of  the  octopus,  and  the 
name  of  a  large  ray  of  Southern  waters,  a  real  fish,  the  Cephalop- 
tera,  known  in  its  localities  as  devil-fish.  This  monstrosity  of  the 
novelist's  imagination  has,  however,  done  more  to  acquaint  the 
general  public  with  these  interesting  cephalopods  than  have  the 
descriptions  of  scientists. 

The  giant  squid,  which  is  such  a  dangerous  foe,  has  its  own 
enemy  in  the  sperm-whale.  The  cachalot  swims  through  the 
water  with  its  lower  jaw  hanging,  the  cephalopod  grasps  the  jaw, 
and  the  whale  then  shuts  his  capacious  mouth  upon  it.  Whale- 
men describe  conflicts  between  these  enormous  creatures,  the 
whale  always  being  the  conqueror.  Sperm-whales  killed  by  man 
often  eject  great  quantities  of  the  squids  in  their  death  throes, 
showing  this  food  to  be  almost  their  exclusive  diet. 

The  name  "cephalopod,'"  meaning  "feet  around  the  head,"  is 
descriptive  in  part  of  their  anatomy.  The  head  is  usually 
marked  off  by  a  neck-constriction,  and  it  bears  two  highly 
organized  eyes.  The  foot  is  fused  in  part  with  the  head  above 
the  ejes  and  around  the  mouth ;  on  the  upper  side  it  is  divided 
into  eight  or  ten  long  arm-like  processes,  bearing  suckers,  which 
act  as  organs  of  prehension.  The  under  part  of  the  foot  forms  a 
tube  called  the  funnel.  Through  the  funnel  the  animal  expels 
water  from  the  mantle  cavity,  and  thus  propels  itself  through 
the  water. 

The  mantle  covers  the  body  of  the  animal,  and  is  a  cup-shaped 
or  conical  envelope,  open  only  at  the  anterior  end,  through  which 
project  the  head  and  siphon  or  funnel.  It  is  attached  to  the 
body  by  a  line  on  the  dorsal  side,  the  anterior  margin  being  free 
and  open,  but  provided  with  an  arrangement  of  cartilages  by 
which  it  can  be  hooked  on  to  the  siphon,  thus  completely  closing 
the  entrance  to  the  mantle  cavity.  The  mantle  is  very  muscular, 
and  is  constantly  expanding  and  contracting,  taking  water  into 
the  mantle  cavity  through  the  mantle  opening  for  respiratory 
purposes,  or  expelling  it  through  the  siphon  for  propulsion ;  in 
the  latter  case  the  mantle  opening  is  closed  at  the  moment  of 
ejecting  the  water.     When  the  siphon  is  in  its  normal  position 


CEPHALOPODS  467 

the  animal  swims  backward ;  but  it  can  be  turned  back  over  the 
edge  of  the  mantle,  giving  a  forward  movement. 

The  surface  of  the  mantle  is  covered  with  pigment-cells  [cliro- 
matophores).  There  are  sets  of  chromatophores  containing  differ- 
ent colors.  The  cells  are  opened  or  closed  at  will  by  muscular 
action  of  their  walls.  When  open  the  cells  seem  to  fuse  together, 
giving  a  solid  color-surface,  or  spots  of  color  as  desired,  in  blue, 
red,  yellow,  or  brown  5  when  closed  they  seem  as  specks  on  the 
almost  transparent  tissues  of  the  animal.  Flashes  of  changing 
color  follow  one  another  with  great  rapidity  over  the  living  ani- 
mal.    In  swimming  it  assumes  the  color  of  its  surroundings. 

Another  curious  means  of  protection  possessed  by  the  dibran- 
chiate  cephalopods  is  an  ink-bag,  the  brown  or  black  secretions 
of  which  are  ejected  through  the  siphon,  clouding  the  water  when 
the  animal  wishes  to  escape  from  danger.  The  ink  taken  from 
the  ink-sac  of  Sepia  is  an  article  of  commerce. 

Only  Natttilus  and  the  female  Argonauta  have  the  characteristic 
external  shell  of  mollusks.  In  all  other  forms  the  sjiell  is  internal 
or  is  invested  in  the  integument  of  the  mantle.  Of  such  is  the 
cuttlebone  of  commerce,  which  is  a  calcareous  leaf-like  body 
obtained  from  Sepia,  the  cuttlefish.  The  common  squid  LoUgo 
has  a  horny  substance  situated  in  the  dorsal  side  of  the  mantle, 
called  the  pen.  Spirula  has  a  spiral  internal  shell  divided  into 
chambers.  Vast  numbers  of  these  shells  are  cast  upon  the 
beaches  of  the  Pacific  Islands,  and  they  have  also  been  found  on 
the  shore  of  Nantucket. 

Cephalopods  are  separated  into  two  subclasses.  In  the  first,  the 
Tetrahranchiata,  there  are  four  branchige,  four  nephridia,  and  four 
auricles.  They  are  without  an  ink-sac,  and  have  the  foot  divided 
into  lobes  bearing  sheathed  tentacles.     Nautilus  is  the  only  genus. 

SUBCLASS  TETRABRANCHIATA 

Genus  Nautilus 
Probably  the  best-known  cephalopod  is  Nautilus — the  pearly- 
shelled,  chambered  nautilus  made  immortal  in  the  beautiful  poem 
of  Oliver  Wendell  Holmes.     The  shell  of  Nautilus  is  a  flat  spiral ; 
the  interior  is  divided  by  septa  forming  a  series  of  chambers; 


468 


MARINE  INVERTEBRATES 


the  septa  are  perforated,  and  through  the  opening  runs  a  tube  or 
prolongation  of  the  body,  the  siphuncle,  which  extends  to  the  tip  of 
the  shell.  The  chambers  are  filled  with  gas.  The  animal  in  the 
course  of  its  growth  moves  forward  into  a  newly  formed  chamber 
and  builds  a  new  septum,  closing  the  cavity  last  occupied.  Nau- 
tilus lives  among  the  coral  reefs  of  the  southern  Pacific.  Its 
four  or  five  species  are  the  remnants  of  a  once  very  extensive  race 
of  cephalopods.  The  fossil  remains  of  many  species  of  JSFcmtUus, 
together  with  various  other  genera  of  shell-bearing  cephalopods, 
indicate  that  this  group  has  seen  its  best  days.  The  dibranchiate 
genera,  however,  appear  to  have  reached  their  maximum  at  the 
present  day. 

SUBCLASS   DIBEANCHIATA 

The  second  subclass,  the  Dihranchiata,  is  characterized  by  two 
branchiae  and  two  auricles.     The  main  part  of  the  foot  is  divided 
into  eight  or  ten  long  arms  provided  with  numer- 
suckers  arranged  in  from  one  to  four  rows 
the  ventral  side  of  the  arms.     They  have 
Iso   an    ink-sac.     The   Dtbrancliiata   are 
divided  into  two  orders :    the  Octopoda, 
which  have  eight  arms,  and  comprise 
the  Octopus  and  Argonauta ;  and  the 
Becapoda,  which  have  ten  arms, 
and  comprise  Spirula,  Omma- 
stre])Jies,  Sepia,  and  Loligo. 
In  these  animals  two  of 
the  ten   arms  are  longer 
than  the  others,  and  these 
tentacular    arms    have 
suckers  only  on  their 
broadened,    club-like 
ends,  they  are  kept 
retracted         within 
grooves,  one  on  each 
side  of  the  head,  ex- 
cept when  needed  for 

Argonaiita  argo,  female  removed  from  shell.  P^  eiicnfelOn. 


CEPHALOPODS 


469 


Argonauta  argo,  side  view  of  shell. 


Genus  Argonauta 

A,  argo.  In  this  species,  the  paper-nautilus,  the  shell,  which  is  pos- 
sessed only  by  the  female,  is  not  chambered.  The  animal  rests  in  the 
shell,  but  has  no  or- 
ganic connection 
with  it  other  than  by 
the  membranous  ex- 
pansions at  the  ex- 
tremities of  the  two 
dorsal  arms,  which 
secrete  it  and  hold  it 
in  place.  The  pur- 
pose of  the  shell  is 
to  hold  and  protect 
the  eggs. 

Genus  Loligo 

L,  JPealei,  In  this 
species  the  body  is 
cylindrical,  tapers  to  a  point,  and  has  a  flat  appendage  in  front.  The 
fins  are  terminal,  half,  or  more  than  half,  as  long  as  the  body,  united  in 
a  point  posteriorly,  and  obtusely  rounded  on  the  outer  angles.  The 
head  is  a  little  narrower  than  the  mantle.  There  are  eight  sessile,  sub- 
triangular  arms  furnished  with  two  series  of 
suckers  which  are  hemispherical  and  stalked,  and 
two  long  retractile  tentacular  arms  dilated  at  the 
extremities,  bearing  four  rows  of  suckers.  It  has 
a  pen-  or  quill- shaped  cartilaginous  substance  in 
the  dorsal  integument  of  the  mantle.  Common 
from  Cape  Cod  to  South  Carolina. 

i.  brevis.     A  small  short-bodied  species,  with 
short  rounded  caudal  fins.     It  is  common   from 
South  Carolina  to  Florida,  and  extends  as  far  north 
j        as  Delaware  Bay. 

Genus  Ofnmastrephes 

O.  illecehrosus.  A  species  similar  to  L.  Pealei, 
but  with  shorter  fins.  These  are  broad  and  pear- 
shaped,  one  third  wider  than  they  are  long,  and 
usually  reach  less  than  one  half  the  length  of  the 
mantle.  They  are  straight  on  the  posterior  end, 
and  form  nearly  a  right  angle,  while  the  upper 
margins  are  rounded.  The  head  is  as  broad  as  the 
mantle.  The  arms  are  stout  and  taper  to  an  acute 
point.  The  tentacular  arms  are  k)ng  when  ex- 
panded. The  species  is  abundant  irom  Cape  Cod 
to  Newfoundland,  and  is  found  as  far  south  as 
Loligo  Peaiei,  young  f e-  Nc wport,  Rhode  Island  This  is  the  squid  which  is 
male ;  dorsal  view.         uscd  SO  extensively  in  the  Banks  fishery  as  bait.    It 


470 


MARINE   INVERTEBRATES 


visits  the  shores  in  large  schools,  presumably  in  pursuit  of  prey,  and  often 
itself  becomes  the  victim.  It  is  a  beautiful  creature  from  its  varying 
colors,  which  are  truly  wonderful.  It  changes  in  a  moment  from  vivid 
red  to  deep  blue,  purple,  orange,  and  so  on,  the  colors  often  passing 
over  it  in  flashes  as  it  swims  along. 


'0*''.'!''  Vil; 


Ommastrephes  illecebrosus,  j^ouni 
male ;  ventral  view. 


VIII 

CHOEDATA 


TABLE  SHOWING  THE  CLASSIFICATION  OF  THE  CHORDATA 
DESCRIBED  IN  THIS  CHAPTER 

Phylum 

CHOKDATA 

•>  Class 

UBOCHORDA  or  TUNICATA 

Order  LARVACEA 

(Free-sioimming,  pelagic ;    Tunicata  having  caudal  appendages) 

Suborders  Genera 

Appendicularia 

Order  THALIACEA 

(Free-swimming  Tunicata,  ivithout  caudal  appendages ;  single  or  in  colonies ;  muscles 
of  hody-ivall  arranged  in  complete  or  m  interrupted  ring-like  bands) 

CYCLOMYARIA 

(Cask-shaped  bodies  with  com%)lete  rings 
of   muscular  bands ;  oral  and    atrial   J  f)oliolutfl 
apertures     at    opposite    ends    of     the 
body) 

HEMIMYARIA 

( Spindle-shaped  bodies ;  muscular  bands    ^ 
in  incomplete  rings ;   oral  and  atrial    )  ScilpCl 
apertures  subterminal) 

PYROSOMATA 

(Hollow  cylindrical  colonies ;  zooids  on- 
bedded  in  a  gelatinous  ivall ;  oral  aper-   <^  PtlTOSOTH€L 
tures  open  on  the  outer,  atrial  apertures 
open  on  the  inner  surface  of  cylinder) 

472 


CHOEDATA 


473 


Suborders 


Genera 
Order  ASCIDIACEA 


Species 


(Mostly  fixed  Tunicata ;  single  or  in  colonies ,-  tests  of  considerable  thickness) 


ASCIDIA  SIMPIICES 

(Possess  distinct  tests  ;  usually  perma- 
nently fixed) 


ASCIDIA  COMPOSITE 

(Fixed  colonies ;  the  zobids  embedded  in  a 
common  gelatinous  material ;  without 
separate  tests) 


Molgula 

Cynthia 

Boltenia 
Ascidia 


Botryllus 
Amaroecium 


i  M,  manhattensis 
\  M,  pellucida 
(  M,  arenata 
i  C,  pyriformis 
\  C.  partita 
(  C,  carnea 
B,  clavata 
( A,  amphora 
I  A,  callosa     . 

B,  gouldii 
A,  pellucidufn 


CHOEDATA 

CLASS  UROCHOEDA  or  TUNICATA 

THE  most  conspicuous  animals  of  this  class  are  tlie  ascidians, 
which  are  common  objects  on  rocky  coasts.  The  simple 
ascidians  are  peculiar  leathery,  sac-shaped  bodies  which  send  out 
jets  of  water  when  touched.  This  habit  gives  them  the  common 
name  of  /'  sea-squirts."  Some  are  highly  colored,  especially 
those  of  Southern  waters ;  others  are  somber,  unattractive  bodies, 
often  growing  in  masses.  The  compound  ascidians  are  gelatinous 
colonies,  sometimes  forming  thin  incrustations,  sometimes  jelly- 
like masses,  on  seaweeds,  shells,  etc.  This  class  comprises  also 
the  beautiful  Salpa,  a  genus  of  free-swimming  animals  having 
transparent  bodies  encircled  by  rings  of  muscular  bands,  and  in 
one  stage  forming  chains  of  attached  organisms  which  swim  on 
the  surface  of  the  sea  and  of  bays. 

The  tunicate s  are  by  some  authors  classed  with  the  vertebrate  ani- 
mals because  in  the  larval  stage  they  have  a  notochord ;  this  disap- 
pears, however,  in  the  adult  form,  and  the  animals  are  considered 
degenerates.  The  tunicates  are  interesting  to  biologists  from  the 
remarkable  changes  they  undergo  in  their  life-history,  and  (in  some 
genera)  the  marked  phase  of  alternation  of  generation.  One  of 
their  curious  anatomical  features  is  the  blood-vascular  system. 
The  circulation  is  propelled  by  wave-like  contractions  of  the 
heart,  which,  after  forcing  the  blood  one  way  for  a  time,  stops 
and  reverses  the  blood-current.  The  tunicates  are  widely  dis- 
tributed, and  occur  at  all  depths.    (Plate  LXXXV.) 

474 


TUNICATES  AND  ASCIDIANS 


475 


G-ENus  Salpa 

The  animals  of  this  genus  are  transparent,  subcylindrical, 
smooth,  gelatinous  bodies  encircled  by  bands  of  white  muscular 
fiber.  They  strikingly  exemplify  alternation  of  generations. 
They  occur  in  two  distinct  conditions,  one  being  solitary,  the 
other  consisting  of  animals  united  in  chains.     The  solitary  indi- 


viduals are  about  an  inch  long,  and 
processes    at    the    posterior    end. 
mals  reproduce  by.  budding,  and 
viduals  in  small  chains,  the  ani- 
in  two  rows.    The  chains  grow 
foot  or  more,   and  contain 
of  salpas.    Each  of  these 
produces  in  turn  a  sin- 
single  Salpa,  and  this 
reproduces   by  bud- 
alike  only  in  alter- 
ist  Chamisso,  who 
tween   the  two 
Salpa    mother 


have  two  long 

These  single  ani- 

form  series  of  indi- 

mals  being  arranged 

to    the    length    of    a 

twenty  to    thirty  pairs 

connected         individuals 

gle  Qg^,  which   becomes  a 

again,  like  its  grandmother, 

ding.     Thus    the   animals   are 


nate  generations.  The  natural- 
discovered  the  relationship  be- 
forms,  expressed  it  as  follows :  a 
is  not  like  its  daughter  or  its  mother, 
but  resembles  ^^^^^^'-  '^^'^i^-  its  sister,  its  grandmother,  and  its  grand- 
daughter. The  single  zooids  liberate  many  colonies  during  the 
summer,  which  grow  rapidly,  and  in  the  autumn  the  chains  are 
exceedingly  abundant.  The  Salpa  chains  swim  about  with  a  ser- 
pentine mov^ement,  and  are  beautiful,  delicate  objects  with  their 
transparent  bodies  banded  with  white,  tinged  with  pink,  and 
streaked  with  blue. 

SIMPLE   ASCIDIANS 

These  are  solitary  and  usually  fixed ;  they  are  never  free-swim- 
ming, and  when  in  colonies  each  animal  has  a  distinct  test.  All 
the  larger  ascidians,  or  sea-squirts,  belong  to  this  group. 

Genus  Molgula 
Body  more  or  less  globular,  membranous,  attached  or  free ; 
orifices  on  very  contractile  tubes. 

M.  fnanhattensis.  Nearly  globular  when  the  tubes  are  contracted ; 
usually  covered  with  bits  of  eel-grass,  seaweeds,  sand,  etc. ;  surface  a 


476  MARINE  INVERTEBRATES 

little  rough ;  color  olive-green.  The  animal  is  often  attached  to  rocks, 
more  frequently  to  eel-grass  and  seaweeds,  and  is  sometimes  so  crowded 
as  to  form  large  clusters.     Found  from  Maine  to  North  Carolina. 

M,pellucida,  Body  nearly  globular,  about  an  inch  in  diameter, 
smooth,  clean,  and  translucent,  the  intestine  showing  through  the  test. 
The  two  tubes  are  large,  swollen  at  the  base,  and  divergent.  The  animal 
lives  free  in  the  sand,  and  is  found  from  Massachusetts  to  North 
Carolina. 

M.  arenata.  Body  somewhat  compressed  laterally  -,  test  thin  and 
covered  completely  with  sand,  which  is  closely  adherent ;  about  three 
quarters  of  an  inch  in  diameter ;  tubes  short  and  wide  apart.  Found  on 
shelly  and  sandy  bottoms  of  bays  and  sounds. 

GrENus  Cynthia 

The  animal  is  attached,  the  body  coriaceous,  and  the  orifices 
four-lobed.  Frequently  associated  in  groups,  the  individuals 
often  differing  in  color. 

C.  pyriformis.  Body  globular,  or  oblong  when  extenaed;  hard, 
velvety,  whitish  surface,  with  pink  cheeks ;  orifices  on  prominent  pro- 
tuberances on  the  upper  surface.  It  lives  in  clear,  deep  water  on  rocks, 
and  is  sometimes  found  at  low-water  mark  on  the  northern  New  England 
coast.    Commonly  called  the  sea-peach.     (Plate  LXXXV.) 

C.  partita.  Body  oblong ;  attached ;  test  horny  and  wrinkled ;  rusty- 
brown  ;  apertures  square,  on  prominent  tubes  marked  with  triangular 
spots  of  white  and  purple ;  diameter  one  inch.  Found  on  the  piles  of 
wharves  and  on  shelly  bottoms  in  shallow  water ;  also  on  the  under  side 
of  stones  when  they  are  much  flattened. 

C  car^nea.  Test  low  and  flat,  with  a  thin  margin  j  adherent  by  a  very 
broad  base  -,  orifices  small,  square,  slightly  prominent ;  red  or  flesh-color. 
Found  in  deep  water  on  stones  and  shells  on  the  northern  New  England 
coast. 

GrENus  Boltenia 

Body  more  or  less  globular,  on  a  long  stem ;  fixed ;  orifices  on 
the  side. 

S,  clavata.  Body  long,  wrinkled,  leathery,  on  a  long  stalk,  resem- 
bling the  flower  of  lady's- slipper  [Cypripedium) ;  two  cross-shaped  ori- 
fices wide  apart  on  the  side  -,  yellowish  in  color ;  attached  to  stones  in 
deep  water,  but  sometimes  washed  ashore  in  storms.  The  stalks  are 
often  covered  with  polyzoans  and  hydroids.     (Plate  LXXXV.) 

G-ENus  Ascidia 

Test  gelatinous  or  cartilaginous ;  attached ;  it  grows  in  bunches 
under  stones  at  low-water  mark.     Sometimes  it  is  variously  col- 


PLATE  LXXXV. 


ASCIDIANS. 

1,  Ascidia  callosa.  5,  Cynthia  placenta, 

2,  Botryllus  Sclilosseri.  6,  Glandula  fibrosa. 

3,  Cynthia  pyriformis.  7,^  Cynthia  couclylomata. 

4,  The  same,  enlai-ged,  8,  Boltenia  clavata. 

9,  Cynthia  echinata. 


TUNICATES  AND  ASCIDIANS  477 

ored,  but  otherwise  it  is  repulsive  in  aspect.     The  apertures  are 
wide  apart ;  one  orifice  is  eight-lobed,  the  other  six-lobed. 

A.  anixyhora.  Form  usually  globular,  but  more  or  less  irregular  ;  sub- 
stance something  like  rubber.  Found  of  all  sizes  adhering  in  clusters  to 
stones,  shells,  and  piles,  and  usually  covered  with  marine  growths.  The 
color  is  grayish-brown. 

A,  ccdlosa.  Body  depressed,  usually  oval,  but  varying  in  shape  j 
thick,  fleshy,  translucent ;  surface  uneven ;  apertures  dark  purple  and 
prominent.  Found  at  low  tide  adhering  to  stones  and  shells.  (Plate 
LXXXV.) 

COMPOUND  ASCIDIANS 

Ascidians  of  this  group  form  fixed  colonies,  and  are  embedded 
in  gelatinous  material,  the  animals  having  a  common  test,  but  not 
being  united  by  any  internal  union.  The  colonies  thus  formed 
are  flat  and  incrusting,  or  are  branched  and  lobed,  or  sometimes 
elevated  on  stalks.  The  zooids  are  in  some  cases  dotted  irregu- 
larly over  the  entire  surface,  in  others  are  in  rows,  or  again  are 
in  groups.  They  have  various  colors — purple,  yellow,  blue,  gray, 
and  green.  They  are  common  on  eel-grass,  the  piles  of  wharves, 
the  bottoms  of  boats,  and  so  on. 


Genus  JBotryllus 

B.  gouldii.  This  species  forms  thick,  fleshy,  translucent  incrustations, 
often  several  inches  in  length  and  a  quarter  of  an  inch  wide,  over  eel- 
grass,  the  piles  of  wharves,  and  other  objects.  Sometimes,  at  the  end  of 
summer,  small  objects  are  completely  covered  with  the  luxuriant  gTowth 
of  this  compound  ascidian.  The  zooids  form  circular  or  elhptical 
groups,  often  as  many  as  fifteen  surrounding  each  orifice,  looking  like 
minute  stars.  The  colonies  vary  in  color.  Often  on  the  same  stem  of 
eel-grass  will  be  found  separate  colonies  varying  in  this  respect.  In 
some  the  ground-color  will  be  olive-green  specked  with  white,  while  the 
zooids  are  purple,  marked  with  other  colors  ;  again  the  arrangement  is 
quite  different. 

G-enus  Afnarcecium 

A,  pellucidum,  A  massive  compound  ascidian,  smooth,  translucent, 
and  gelatinous,  which  forms  large,  hemispherical,  complex,  irregular 
masses  six  inches  or  more  in  diameter.  It  is  usually  covered  by  adhering 
sand.  The  mass  consists  of  club-shaped  lobes,  which  rise  from  a  common 
base.  Each  lobe  contains  a  central  orifice  around  which  long,  slender 
zooids,  sometimes  an  inch  long,  are  grouped.  These  masses  are  so  abun- 
dant in  some  places  that  they  cover  the  bottom  for  considerable  spaces. 
They  are  found  in  deep  water  from  Cape  Cod  to  North  Carolina. 


INDEX 


Heavy-faced  type  is  used  to  indicate  names  of  classes,  orders,  genera,  etc. ;  heavy- 
faced  numerals  to  indicate  the  place  where  the  fullest  description  is  given 


Abdomen,  243,  246. 
Abductor  muscles,  302. 
Aboral,  202. 

Surface,  201. 
Abyssal,  23, 
Acalephs,  134. 
Acanthalithodes,  240,  271. 

A.  hispidus,  240,  271. 
Acephala,  409. 
Acetabularia,  51,  57. 

A.  crenulata,  51,  57- 
Acmsea,  9,  309,  312. 

A.  mitra,  324,  357. 

A.  patina,  324,  357. 

A.  testudinalis,  41,  42,  324, 
343,  348,  356. 

A.    testudinalis,    var.     al- 
veus,  324,  357. 
Acmaeidae,  324,  356. 
Acontia,  145. 
Acorn-shell,  254. 
Actiniaria,  141,  142,  143,  144. 
Actinozoa,  112,  115,  141,  142. 
Adamsia  palliata,  144,  267. 
Adductor   muscles,    302,    413, 

417. 
.^olididae,  324. 
.ffiolis,  41,  42,  309,  324,  354. 

M.  papulosa,  324,  354. 
iEquoreidce,  116,  128. 
iEtea,  188,  194. 

M.  anguinea,  188,  194. 
Agarum,  36,  42,  63,  68,  69. 
Aglaophemia,  127. 

A.  struthioides,  116,  127. 
Ahnfeldtia,  76,  82. 

A.  plicata,  76,  82. 
Alaria,  63,  69. 

A.  esculenta,  41,  42,  63,  6g. 
Albunaea,  240,  269, 

A.  gibbesii,  240,  269. 
Alcyonacea,  141,  151. 
Alcyonaria,  141,  142,  150,  152. 
Alcyonidium,  189,  192,  197. 

A.  hirsutum,  189,  197. 

A.  hispidum,  189,  198. 

A.  parasiticum,  189,  ig8. 

A.  ramosum,  189,  197. 
Alcyonium,  141,  151. 

A.  palmatum,  141,  150,  151. 
Aleutian  province,  311. 
Algae,  25,  48,  62,  76. 

Botanical  facts  about,  25. 


Alternation  of  generation.  120, 

121. 
AmarcEcium,  473,  477. 

A.  pellucidum,  473,  477. 
Ambulacra,  201,  202,  205,  214, 

218. 
Ambulacral  groove,  205. 

Ossicles,  205. 

Zones,  201,  202,  205,  218,  229. 
American  division,  24. 
Amphictenidee,  162,  183. 
Amphineura,    300,    316,   317, 

320,  321,  323. 
Amphipoda,  242,  289. 
Amphissa,  312. 

A.  corrugata,  326,  389. 
Amphitrite,  161,  182. 

A.  ornata,  161,  182. 
Amphiura,  213,  215, 

A.  squamata,  213,  215. 
Ampullae,  201,  205,  206,  218. 
Anadyomene,  51,  57. 

A.  fiabellata,  51,  57. 
Anatomy,  20. 

Of  higher  Crustacea,  246. 
Anemone  Cave,  40. 
Angel's-wings,  461. 
Animal-flowers,  142. 
Animal  life  in  its  lowest  forms, 

21. 
Annelida,  305. 
Annulata,  159,  161,  164,  170. 
Anomia,  405,  424. 

A.  aculeata,  405,  425. 

A.  lampe,  405,  425. 

A.  simplex,  405,  424. 
Anomiidae,  405,  424. 
Anomura,  240,  264. 
Antennse,  243,  246,  258. 
Antennules,  243,  246,  258. 
Antheneidffi,  204,  209. 
Anthomedusae,  116. 
Aperture,  302. 
Apex,  348. 
Aphrodite,  161,  174. 

A.  aculeata,  I6l,  174. 
Aphroditidae,  161,  172,  173. 
Aplacophora,  300,  321,  323. 
Aplysella  violacea,  105. 
Aplysia  'Wilcoxii,  352. 
Aplysiidae,  324. 
Apoda,  228,  233. 
Appendicularia,  472. 
Arabella,  161,  179. 

A.  opalina,  161,  179. 
Arbacia,  217,  222. 

479 


A.  punctulata,  217,  222. 
Arbaciadse,  217,  222. 
Area,  310,  405,  425. 

A.  noae,  405,  426. 

A.  pexata,  405,  425. 

A.  ponderosa,  405,  426. 
Arcachon,  434. 
Architeuthis,  465. 
Arcidae,  405,  425. 
Arctic  province,  309. 
Arctica,  406,  441. 

A.  islandica,  406,  441. 
Arenicola,  162,  172,  184. 

A.  marina,  162,  184. 
Arenicolidae,  162,  184. 
Argonauta,  464,  467,  468. 

A.  argo,  464,  469. 
Aristocratic   genera,  313,  377, 

398,  401. 
Aristotle's  lantern,  203. 
Arthrocladia,  62,  67. 

A.  villosa,  62,  67. 
Arthropoda,  238,  244. 
Arthrostraca,  242,  289. 
Articulata,  188. 
Ascidia,  473,  476, 

A.  amphora,  473,  477. 

A.  callosa,  473,  477. 

A.  compositae,  473. 

A.  simplices,  473. 
Ascidiacea,  473. 
Ascidians,  8,  474. 

Compound,  474,  477. 

Simple,  474,  475. 
Ascophyllum,  63,  73. 

A.  nodosum,  43,  63,  73. 
Asperococcus,  62,  66. 

A.  echinatus,  62,  66. 
Astacoidae,  240,  261. 
Astarte,  309,  406,  440. 

A.  castanea,  406,  441. 

A.  undata,  406,  441. 
Astartidae,  406,  440. 
Asterias,  204,  212. 

A.  Forbesii,  204,  207,  212. 

A.  gigantea,  204,  207,  212. 

A.  ochracea,  204,  212. 

A.   vulgaris,    43,    204,   207, 
212. 
Asteriidae,  204,  212. 
Asterina,  204,  210. 

A.  folium,  204,  210. 

A.  miniata,  204,  211. 
Asterinidae,  204,  210. 
Asteroidea,  200,  204,  205. 
Astraea,  141,  146,  147,  148. 


480 


INDEX 


Astrangia,  141,  150. 

A.  danae,  13,  141,  150. 
Astropecten,  204,  209. 

A.  articularis,  204,  209. 
Astropectinidae,  204,  208. 
Astrophyton,  213,  215, 

A.  Agassizii,  213,  215. 
Astyris  gausapata,  326,  389. 
Asymmetrical,  328. 
Aurelia,  133,  137. 

A.  flavidula,  133,  137. 
Auricula,  231. 
Auriculata,  201. 
Avicula,  405,  431. 

A.  atlantica,  405,  431. 
Avicularia,  190,  193. 
Aviculidse,  405,  430. 


Balanus,  239,  250,  254. 

B.  balanoides,  239,  255. 

B.  crenatus,  256. 

B.  eburneus,  239,  255. 

B.  geniculatus,  239,  256. 

B.  ovularis,  255. 

B.  rugosus,  239,  256, 

B.  tintinnabulum,  239,  256. 
Bangia,  78,  96. 

B.fusco-purpurea, 43,78,96. 
Bangiaceae,  78,  96. 
Barnacles,  8,  43,  245,  250. 
Bathymetrical  division,  23. 
Bdelloura,  160,  167. 

B.  Candida,  160,  167. 

B.  rustica,  160,  167. 
Eeach-flea,  245,  289. 
Beak,  417. 
Bela,  309. 
Benthos,  23. 
Bero'ida,  154,  157. 
Bilateral    symmetry,    20,    302, 

320,  321. 
Binomial  nomenclature,  28. 
Bipinnaria,  201. 
Biramous,  243,  257. 
Bittium,  326,  374. 

B.  nigrum,  326. 
Bivalves,    306,  307,    314,    315, 
409. 

Mud-boring,  452. 

Rock-boring,  452,  460. 
Blastostyles,  120. 
Blue  crab,  275. 
Blue-green  seaweeds,    47,    48, 

49. 
Body-whorl,  304,  343. 
Bolina,  154,  156. 

B.  alata,  154,  156. 

B.septentrionalis,154, 156. 

B.  vitrea,  154,  156. 
Boltenia,  473,  476. 

B.  clavata,  473,  476. 
Bopyridae,  292. 
Boreal,  23. 

Boring  amphipod,  290. 
Boring-sponges,  105. 
Bostrychia,  77,  89. 

B.  rivularis,  77,  89. 
Botanical  facts  about  algae,  25. 
Botryllus,  473,  477. 


B.  gouldii,  473,  477. 
Bougainvillea,  124. 

B.  superciliaris,  116,  124. 
Box-crab,  287. 
Brachyura,  241,  258,  272. 
Brain-corals,  146. 
Branchise,   302,   319,  329,  336, 

413- 

Dermal,  208. 
Branchiolaria,  201. 
Brissopsis,  217,  227. 

B.  lyrifera,  217,  227. 
"Brit,"  249. 

Brittle-stars,  43,  200,  214. 
Brown  bodies,  190,  193. 
Bryopsis,  51,  59. 

B.  plumosa,  51,  59. 
Bryozoa,  191. 
Buccal  mass,  302,  317. 
Buccinidae,  327,  391. 
Buccinum,  12,    309,   313,  327, 
330,  392. 

B.    undatum,    42,    44,   314, 
327,  331,  392. 
Bucidiumparasiticum,  144. 
Bugula,  188,  192,  193,  195. 

B.  flabellata,  188,  196. 

B.  Murrayana,  188,  196. 

B.  turrita,  43,  188,  195. 
Bulla,  324,  351. 

B.  nebulosa,  324,  351. 

B.  occidentalis,  324,  351. 

B.  solitaria,  324. 
BuUidae,  324. 
Butterfly-shells,  323. 
Byssus,  415,  426,  432. 


Caberea,  188,  195. 

C.  EUisii,  188,  195. 
Cake-urchins,  218,  224. 
Calappa,  241,  287. 

C.  flamma,  241,  287. 
Calappidae,  241,  287. 
Calcarea,  100,  104,  106. 
Calcareous  hydroids,  129. 

Seaweeds,  31,  147. 
Californiau  province,  312. 
Callinectes,  241,  275. 

C.  hastatus,  12,  275. 

C.  sapidus,  241,  274,  275. 
Calliostoma,  312,  325,  361. 

C.  annulatum,  325,  361. 

C.  canaliculatum,  325,  361. 

C.  costatum,  325,  361. 

C.  jujubinum,  325,  361. 

C.  occidentale,  325,  361. 
Callista,  311,  410. 

C.  gigantea,  450. 

C.  maculata,  450. 
Callithamnion,  15,  78,  79,  90. 

C.  americanum,  78,  90. 

C.  Baileyi,  78,  91. 

C.  byssoideum,  78,  91. 

C.  floccosum,  78,  91. 

C.  Pylaisaei,  78,  91. 

C.  seirospermum,  78,  91. 
Callophyllis,  76,  82. 

C.  laciniata,  76,  82. 

C.  variegata,  76,  82. 


Calothrix,  48,  49. 
Cameo-cutting,  381. 
Campanularians,  116, 121,  125. 
Canal,  302. 

Anterior,  344. 

Posterior,  344. 

System  of  sponge,  103. 
Cancellaria,  310,  327,  402. 

C.  reticulata,  327,  402. 
Cancellariidae,  327,  402. 
Cancellus,  266. 
Cancer,  241,  277. 

C.  antennarius,  241,  280. 

C.  borealis,  241,  277. 

C.  irroratus,  241,  277. 

C.  magister,  241,  278. 

C.  productus,  241,  278. 
Cancroidse,  241,  277. 
Caprella,  8,  242,  291. 

C.  geometrica,  242,  291. 
Capulidae,  325,  369. 
Carapace,  243,  246. 
Carcinides,  241,  274. 

C.  maenas,  241,  274. 
Carcinus  maenas,  41,  274. 
Cardiidae,  407,  453. 
Cardita,  406,  440. 

C.  borealis,  406,  440. 

C.  floridana,  406,  440. 
Carditidae,  406,  439. 
Cardium,   310,   311,   407,   410, 
413,  453. 

C.  corbis,  407,  454. 

C.  elatum,  407,  454. 

C.  islandicum,  407,  454. 

C.  isocardia,  407,  454. 

C.  laevigatum,  407,  454. 

C.  magnum,  407,  453. 

C.  mortoni,  407,  454. 

C.  pinnulatum,  407,  454. 

C.  quadrigenarium,  407, 
454. 

C.  serratum,  407,  454. 

C.  substriatum,  407,  454. 
Caribbean  province,  310. 
Carinated,  302. 
Cartilage,  417. 
Cartilaginous,  27. 
Cassididae,  326,  380. 
Cassiopeia,  133,  140. 

C.  frondosa,  133,  140. 
Cassis,  310,  326,  380. 

C.  cameo,  326,  380. 

C.  inflata,  326,  381. 

C.  Madagascarensis,  381. 

C.  testiculus,  326,  381. 

C.  tuberosa,  326,  380. 
Caudina,  228,  233. 

C.  arenata,  228,  233. 
Caulerpa,  51,  56,  59. 

C.  Mexicana,  51,  60. 

C.  paspaloides,  Plate  VIII. 

C.  plumaris,  Plate  VIII. 

C.  plumosa,  51. 

C.  prolifera,  51,  60. 

C.  Wurdemanii,  51. 
Caulerpaceae,  51,  59. 
Cellepora,  188,  197. 

C.  pumicosa,  188,  197. 

C.  ramulosa,  188,  197. 

C.  scabra,  188,  197. 
Cellularia,  188,  195. 

C.  ternata,  188,  195. 


INDEX 


481 


Cellularina,  188. 
Cenobita,  240,  268. 

C.  diogenes,  240,  268. 
Cenobitidse,  240,  268. 
Cephalic,  243,  246. 
Cephalopoda,    301,   315,    320, 

321,  464. 
Cephalothorax,  243,  246,  272. 
Ceramiese,  78,  90. 
Ceramium,  27,  43,  78,  92. 

C.  diaphanum,  78,  93. 

C.  fastigiatum,  78,  93. 

C.  rubrum,  78,  92. 

C.  rubrum,  var.  proliferum, 
78,   93. 

C.  rubrum,  var.    secunda- 
tum,  78,  93. 

C.  strictum,  78,  93. 

C.  tenuissimum,  78,  93. 

C.  tenuissimum,  var.   pa- 
tentissimum,  78,  93. 
Cerata,  353. 
Cerebratulus,  160,  170. 

C.  angulatus,  160,  170, 
Cerianthus,  144. 
Cerithidea,  326,  375. 

C.  sacrata,  326,  375. 

C.  scalariformis,  326,  375. 
Cerithiidae,  326,  373. 
Cerithium,  326,  374- 

C.  floridanum,  326,  374- 

C.  minimum,  326,  374. 

C.  muscarum,  326,  374- 
Cerostoma,  326,  385,  387. 

C.  foliatum,  326,  385. 

C.  nuttallii,  326,  385. 
Cestida,  154,  157. 
Cestoda,  160. 
Cestum,  154,  157. 

C.  veneris,  154,  157. 
Cetochilus,  239,  249. 
Chaetae,  173. 
Chaetangieae,  76,  80. 
Chaetobranchus,  161,  182. 

C.  sanguineus,  161,  182. 
Chaetomorpha,  51,  53. 

C.  aerea,  51,  53. 

C.  linum,  51,  54. 

C.  melagonium,  51,  53. 

C.  picquotiana,  54. 

C.  tortuosa,  53. 
Chaetopoda,  161,  171. 
Chalinopsilla,  100,  107. 

C.  arbuscula,  100,  107. 

C.  oculata,  100,  107. 
Chamsedoris,  51,  56. 

C.  annulata,  51,  56. 
Champia,  77,  85. 

C.  parvula,  77,  85. 
Charybdaea,  133,  137. 

C.  marsupialis,  133,  137. 
Cheilostomata,  188, 194. 
Chelse,  243,  258. 
Cheliped,  243,  258. 
Chelura,  242,  290. 

C.  terebrans,  13,  242,  290. 
Chicoreus  rufus,  382. 
Chione,  406,  451. 

C.  fluctifraga,  406,  451. 

C.  simillima,  406,  451. 

C.  succincta,  406,  451. 
Chiridotea,  242,  294. 

C.  caeca,  242,  294. 

31 


C.  entomon,  242,  294. 
Chiton,  9,  309,  352. 

C.  albus,  323. 

C.  apiculatus,  323. 

C.  ruber,  41,  323. 

C.  spinosus,  322. 
Chitonidae,  312,  322. 
Chlorophyceae,  28,  47,  51. 
Chlorostoma,  312,  325,  362. 

C.  brunneum,  325,  362. 

C.  funebrale,  325,  362. 
Choanocytes,  102. 
Choanoflagellata,  102. 
Chondria,  77,  90. 

C.  dasyphylla,  77,  go. 

C.  striolata,  77,  90. 

C.  tenuissima,  77,  90. 
Chondrospongise,  100. 
Chondrus,  76,  80. 

C.  crispus,  38,  76,  80. 
Chorda,  63,  68,  6g. 

C.  filum,  63,  69. 
Chordaria,  62,  67. 

C.  flagelliformis,  43,  44,  62, 
67. 
Chordariaceae,  62,  67. 
Chordata,  19,  472,  474. 
Chorus,  312,  326,  388. 

C.  belcheri,  326,  388. 
Chromatophores,  467. 
Chrysodomus,    12,    309,    313, 
327,  392. 

C.  decemcostatus,  327,  392. 
Chylocladia,  77,  85. 

C.  articulata,  77,  85. 
Cidaridae,  217,  222. 
Cidaris,  217,  222. 

C.  tribuloides,  217,  222. 
Ciliary  flames,  164. 
Cinereous,  302. 
Cirolana,  242,  292. 

C.  concharum,  242,  292. 
Cirratulidae,  161,  181. 
Cirratulus,  161,  181. 

C.  grandis,  161,  181. 
Cirri,  172,  302. 
Cirripedia,  239,  250. 
Cirripeds,  251. 
Cistenides,  162,  183. 

C.  Gouldii,  162,  183.' 
Cladocera,  238. 
Cladophora,  26,  51,  54. 

C.  arcta,  51,  54. 

C.  gracilis,  51,  54. 

C.  rupestris,  51,  54. 
Cladostephus,  62,  65. 

C.  verticillatus,  62,  65. 
Clam,  321,  448. 

Giant,  447. 

Hard-shell,  448,  451,  456. 

Little  Neck,  410,  448. 

Soft-shell,  456. 

Worms,  176. 
Classification,  19. 

Of  gasteropods,  348. 

Of  inollusks,  320. 
Clava,  122. 

C.  leptostyla, 116,  122. 
Clibanarius,  240,  267. 

C.  vittatus,  240,  267. 
Cliona,  100,  106. 

C.  sulphurea,  100,  105,  106. 
Cloaca,  229. 


Clymenella,  162,  183. 

C.  torquata,  162,  183. 
Clypeaster,  217,  224. 

C.  ravenellii,  217,  224. 
Clypeastroidea,  217,  224. 
Clytia,  126. 

C.  bicophora,  116,  126. 

C.  poterium,  116,  126. 
Cockles,  453. 
Codiaceae,  51,  59. 
Codium,  51,  59. 

C.  tomentosum,  51,  59. 
CcElenterata,  111,  112,  113. 
Coelopleurus,  217,  222. 

C.  fioridanus,  217,  222, 
Coenosarc,  118. 
Coffee-shells,  379. 
Collecting,  6. 

And  preserving  seaweeds,  15. 

At  Bar  Harbor,  40. 
Columbella,  326,  388. 

C.  avara,  326,  389. 

C.  corrugata,  326,  389. 

C.  gausapata,  326,  389. 

C.  lunata,  326,  389. 

C.  mercatoria,  326,  388. 

C.  similis,  326,  389. 
Columbellidae,  326,  388. 
Columella,  302,  344. 
Comatula,  234,  235. 
Comb-jellies,  112,  115,  155. 
Communal  life,  121. 
Conceptacles,  72. 
Conchs,  377. 
Conch-shell,  376. 
Concrescent,  302. 
Confervaceae,  26,  51,  53. 
Conidae,  327,  401. 
Connostomae,  1J3. 
Conus,  313,  327,  401. 

C.  floridanus,  327,  402. 

C.  gloria-maris,  401. 

C.  pealei,  327,  402. 
Copepoda,  239,  249. 
Corallina,  29,  78,  96. 

C.  officinalis,  41,  43,  78,  96. 

C.  rubrum,  142, 146,  147. 
Coralline  Crags,  192. 

Zone,  30,  31. 
Corallineae,  78,  95. 
Corallite,  146. 
Corallum,  146. 
Corals,  112. 
Cordate,  302. 
Cormophytes,  25, 
Cornacuspongiae,  100. 
Coronula  diadema,  255. 
Corymorpha  pendula,  116. 
Coryne,  116,  123. 

C.  mirabilis,  116,  123. 
Cosmocephala,  160,  170. 

C.  cchracea,  160,  170. 
Costse,  302. 
Cowry-shell,  377. 
Crabe  enrag^,  274. 
Crabs,  244,  247,  272. 

Blue,  275. 

Box-,  287. 

Fiddler-,  241,  282. 

Ghost-,  282. 

Green,  274. 

Hermit-,  264. 

Kelp-,  286. 


482 


INDEX 


Lady-,  276. 

Mud-,  281. 

Oyster-,  287. 

Purple  shore-,  281. 

Red,  278. 

Eock-,  277,  280. 

Sand-,  11,  241,  276,  282. 

Sheep-,  285. 

Shore-,  281. 

Spider-,  241,  284. 

Stone-,  280. 

Swimming,  241,  274. 

Toad-,  285. 

Walking,  241. 

Yellow  shore-,  281. 
Crangon,  240,  260. 

C.  franciscorum,  240,  261. 

C.  vulgaris,  240,  260. 
Crawfish,  240,  259,  261. 
Creeping  Polyzoa,  193. 
Crenulated,  302. 
Crepidula,  825,  369. 

C.  aculeata,  325,  369. 

C.  adunca,  370. 

C.  fornicata,  325,  369. 

C.  navicelloides,  370. 

C.  plana,  325,  369. 

C.  rugosa,  370. 
Cribrella,  204,  207,  211. 

C.  sanguinolenta,  204,  211. 
Crimson  Bluffs,  33. 
Crinoidea,  200,  234. 
Crinoids,  202,  235. 

Fossil,  235. 
Crista,  188,  194- 

C.  eburnea,  188,  194. 
Crossaster,  204,  211. 

C.  papposus,  204,  211. 
Crucibulum,  325,  370. 

C.  spinosum,  325,  370. 

C.  striatum,  325,  370. 
Crustacea,  238,  244,  248,  257, 

262. 
Cryptochiton,  323. 

C.  stelleri,  323. 
Cryptogams,  25. 
Cryptolithodes,  240,  271. 

C.  sitchensis,  240,  271. 
Cryptonemiaceae,  78,  94. 
Cryptozonia,  204,  2ii. 
Crystalline  stylet,  302,  341. 
Cteuidia,  302. 
Ctenodiscus,  204,  208. 

C.  corniculatus,  204,  208. 
Ctenophora,  112,  115, 154,  155. 
Ctenostomata,  189,  197. 
Cubomedusae,  133,  137. 
Cucumaria  crocea,  231. 

C.  laevigata,  231. 
Cumacea,  242,  288. 
Cutleria,  63,  71. 

C.  multifida,  63,  71. 
Cutleriaceae,  63,  71. 
Cuttlefishes,  44,  315,  467. 
Cuvieria  squamata,  232. 
Cuvierian  organs,  231. 
Cyanea,  133,  136,  138. 

C.  arctica,  44,  133,  138,  144. 

C.  fulva,  133,  139. 

C.  versicolor,  133,  139. 
Cyanophyceae,  28,  48,. 49. 
Cyclomyaria,  472. 
Cyclops,  239,  249,  250. 


Cyclostomata,  188,  193. 
Cydippida,  154,  156. 
Cymopolia,  51,  57. 

C.  barbata,  51.  57. 
Cynthia,  473,  476. 

C.  carnea,  473,  476. 

C.  partita,  473,  476. 

C.  pyriformis,  473,  476. 
Cypraea,  326,  334,  377. 

C.  aurantia,  377. 

C.  exanthema,  326,  378. 

C.  moneta,  378. 

C.  spadacea,  326,  379. 

C.  spurca,  326,  378. 
Cypraeidae,  326,  377. 
Cypridina,  238. 

C.  islandica,  441. 
Cyprinidae,  406,  441. 
Cypris,  238. 
Cyrena,  311. 
Cystoclonium,  77,  83. 

C.  cirrhosa,  77,  83. 

C.  purpurascens,  77,  83. 
Cystoseira,  63,  73. 

C.  expansa,  63,  73. 
Cytherea,  406,  450. 

C.  gigantea,  406,  450. 

C.  maculata,  406,  450. 

D 

Dactylopores,  129. 
Dactylozobids,  129. 
Daphnia,  238. 
Dasya,  77,  79,  89. 

D.  elegans,  77,  89. 
D.  plumosa,  77,  89. 

Dasycladaceae,  51,  57. 
Dasycladus,  51,  57. 

D.  occidentalis,  51,  57. 
Decapoda,  240,  257,  301,  468. 
Decussated,  303. 
Delesseria,  77,  79,  86. 

D.  alata,  77,  86. 

D.  Leprieurii,  77,  86. 

D.  sinuosa,  77,  86. 
Delesserieae,  77,  85. 
Dendronotidae,  324. 
Dendronotus,  41,  42,  324,  353. 

D.  arborescens,  324,  353. 
Dentalidae,  327,  402. 
Dentalium,  268,  327,  328,  404. 

D.  dentale,  327,  403. 

D.  hexagonum,  327,  403. 

D.  pretiosum,  327,  403. 
Dermal  branchiae,  208. 
Desmacidonidae,  100. 
Desmarestia,  15,  62,  66. 

D.  aculeata,  43,  62,  66. 

D.  ligulata,  62,  67. 

D.  viridis,  62,  66. 
Desmarestiaceae,  62,  66. 
Desmids,  33. 
Desmosticha,  217,  221. 
Devil's  pocket-books,  12. 
Dextral,  303,  345. 
Diadema,  217,  222. 

D.  setosum,  217,  222. 
Diadematidae,  217,  222. 
Diastopora,  188,  194. 

D.  patina,  188,  194. 
Diastylis,  242,  288. 


D.  quadrispinosus,  242, 288. 
Diatocardia,  300,  324,  356. 
Diatomaceae,  38. 
Diatomaceous  ooze,  21. 
Diatoms,  21,  32. 

Green,  435. 
Dibranchiata,  301,  464,  468. 
Dictyosiphon,  62,  67. 

D.  fceniculaceus,  62,  67. 
Dictyosiphonaceae,  62,  67. 
Dictyota,  63,  70. 

D.  dichotoma,  63,  70. 

D.  fasciola,  63,  70. 
Dictyotaceae,  63,  70. 
Diopatra,  10, 161,  178. 

D.  cuprea,  161,  178. 
Diploria,  141,  148. 

D.  cerebriformis,  141,  148. 
Discomedusae,  133,  137. 
Distribution  of  algse,  30. 

Of  animal  life  in  the  sea,  23. 
Doliidae,  326,  379. 
Doliolum,  472. 
Dolium,  310,  326,  379. 

D.  galea,  326,  379. 

D.  perdix,  326,  379. 
Donacidae,  406,  445. 
Donax,  10,  406,  445. 

D,  californicus,  406,  445. 

D.  variabilis,  406,  445. 
Dorididae,  324. 
Doris,  309,  324,  354. 

D.  bilamellata,  324,  354. 
Dorocidaris,  217,  222. 

D.  Blakei,  217,  222. 

D.  papillota,  217,  222. 
Dorsal  surface,  201,  202. 
Dosinia,  406,  450. 

D.  discus,  406,  450. 

D.  elegans,  406,  450. 
Drill,  383. 

Dromia,  105. 
Dromidae,  240,  264. 
Dulse,  38. 
Dumontieae,  78,  94. 

E 

Ears,  247,  435. 
Of  corn,  12. 
Echidnocerus,  240,  270. 

E.  cibarius,  240,  270. 

E.  foriminatus,  240,  271. 
Echinanthidae,  217,  224. 
Echinanthus,  217,  225. 

E.  rosaceus,  217,  225. 
Echinarachnius,  217,  225. 

E.  excentricus,  217,  225. 

E.  parma,  44,  217,  225. 
Echinaster,  204,  211. 

E.  sentus,  204,  211. 
Echiriasteridae,  204,  211. 
Echinidae,  217,  223. 
Echinodermata,  200,  202,  305. 
Echinoidea,  200,  203,  217,  218, 

221. 
Echinometra,  217,  223. 

E.  subangularis,  217,  223. 
Echinometridae,  217, 223. 
Echinus,  217,  224. 

E.  gracilis,  217,  224. 
Ectocarpaceae,  28,  62,  64. 


INDEX 


483 


Ectocarpus,  28,  29,  62, 64. 

E.  Hooperi,  29. 

E.  littoralis,  62,  64. 

E.  siliculosus,  62,  65. 

E.  tomentosus,  62,  65. 

E.  viridis,  62,  65. 
Ectoderm,  loi,  118. 
Ectoprocta,  188,  193. 
Edwardsia,  144. 
Eel-grass,  12. 
Egg-capsules,  314. 
Egsr-cases,  n,  12,  367. 
Eggs,  248,  814,  343,  414. 
Elachista,  62,  67. 
Elachistaceae,  67. 
Elytra,  173. 
Embryology,  20. 
EnccEliaceae,  62,  65. 
Encope,  217,  226. 

E.  michelini,  217,  226. 
Endendrium  ramosum, 

Plate  XLI. 
Endoderm,  loi,  118. 
Endopodite,  243,  246. 
Ensis,  310,  407,  458. 

E.  americanus,  458. 

E.  directus,  407,  458. 
Entalis,  327. 

E.  striolata,  327,  403. 
Enteromorpha,  26,  30,  51,  55. 

E.  clathrata,  51,  55. 

E.  compressa,  51,  55. 

E.  intestinalis,  51,  55. 

E.  lanceolata,  51,  56. 
Entomostraca,  238,  249. 
Entoprocta,  189,  198. 
Ephyrula.  136. 
Epialtus,  241,  286. 

E.  productus,  241,  286, 
Epidermis,  303,  345,  347. 
Epimera,  243. 
Epipodite,  243. 
Epistoma,  243. 
Epizoanthus       americanus, 

267. 
Equilateral,  418. 
Equivalve,  418. 
Erect  Polyzoa,  103. 
Errantia,  161,  173,  180. 
Escharella,  188,  197. 

E.  variabilis,  188,  197. 
Escharina,  188. 
Escutcheon,  418. 
Esperiopsis,  100. 

E.  quatsinoensis,  100. 
Eucheuma,  77,  84. 

E.  isiforme,  77,  84. 
Eucope,  125. 

E.  diaphana,  116,  125. 
Eucratea,  188,  195. 

E.  chelata,  188,  195. 
Eudendrium  ramosum,  116. 
Eugorgia    aurantica,    Plate 

XLVI. 
Eulamellibranchiata,       301, 

406,  420,  438. 
Eunicea      lugubris,       Plate 

XLVII. 
Eunicidffi,  161,  178. 
Eupagurus  kroyeri,  267. 

E.  prideaux,  267. 

E.  pubescens,  267. 
Eupanopeus,  241. 


E.  herbstii,  241,  281, 
Euphausia,  239,  247. 
Euphyllopoda,  238. 
Eupleura,  326,  384. 

E.  caudata,  326,  384. 
Euryalida,  213,  215. 
Eurypanopeus,  241. 

E.  depressus,  241,  281. 
Euspongia,  100,  107. 

E.  officinalis,  100,  107. 

E.  officinalis,  var.   adriat- 
ica,  100,  108. 

E.    officinalis,    var.    dura, 
100,  108. 

E.  officinalis,  var.  mollis- 
sima,  100,  108. 

E.  officinalis,  var.  rotunda, 
100,  108. 
Euspcnginae,  100. 
Euthora,  77,  83. 

E.  cristata,  77,  83. 
Exopodite,  243,  246. 
Exoskeleton,  20],  203,  205. 
Ex-umbrella,  120. 
Eyes,  247,  322,  333,  415,  416. 


Family,  20. 

Fasciolaria,  311,  327,  331,  397. 

F,  distans,  327,  397. 

F.  gigantea,  327,  397. 

F.  tulipa,  .327,  397- 
Fasciolariidse,  327. 
Feather-stars,  200,  234. 
Fenja,  144. 

Fiddler-crabs,  12,  241,  282. 
Filamentous  plants,  26. 
Filibranchiata,  301,  405,  420, 

423- 
Finger-pores,  129. 
Fissurella,  324,  357. 

F.  alternata,  324,  357. 

F.  aspersa,  324. 

F.  barbadensis,  324,  357. 
Fissurellidae,  324,  357. 
Flagellate  Infusoria,  102. 
Flat  worms,  164. 
Florideae,  28,  31,  76. 
Flustra,  188,  196. 

F.  foliacea,  192. 

F.  membranacea,  188,  196. 
Flustrina,  188. 
Foot,  303,  317, 320,  321, 328, 415. 

Gasteropod,  334. 
Foraminifera,  21,  22. 
Fossette,  303,  418. 
Fovia,  160,  167. 

F,  Warrenii,  160,  167. 
Free-swimming  colonies,  130. 
Frond,  26. 

Fucaceae,  27,  63,  71. 
Fucus,  15,  17,  SO,  63,  64,  72. 

F.  ceranoides,  63,  73. 

F.  furcatus,  63,  73. 

F.  serratus,  63,  73. 

F.  vesiculosus,  38,  63,  72. 
Fulgur,  10,   11,  310,  314,  327, 
330,  394. 

F.  canaliculata,  12,  327,  395- 

F.  carica,  12,  327,  395. 


F.  perversa,  327,  396. 

F.  pyrum,  327,  396. 
Functional  siphon,  331. 
Fuscous,  303. 
Fusiform,  303. 


G 

Gammarus,  9,  43,  242,  290. 

G.  annulatus,  290. 

G.  locusta,  242,  290. 

G.  mucronatus,  290. 
Gasteropoda,   300,    320,    ,324, 

328,  335. 
Gastric  mill,  243,  247. 
Gastropores,  129. 
Gelasimus  minax,  282. 

G.  pugilator,  282. 

G.  pugnax,  282. 
Gelatinous,  27. 
Gelidiese,  76,  80. 
Gelidium,  76,  80. 

G.  corneum,  76,  80. 

G.  Coulteri,  Plate  XVII. 
Generic  name,  28. 
Genus,  20. 

Geographical  distribution,  308. 
Gephyrea,  171,  1^5. 
Geryonopsidae,  116,  128. 
Ghost-crab,  282. 
Giant  crab  of  Japan,  244. 
Gigartina,  28,  76,  81. 

G.  mamillosa,  76,  81. 

G.  microphylla,  76,  81. 

G.  radula,  76,  81. 

G.  spinosa,  76,  81. 
Gigartinaceae,  28,  76,  80. 
Gills,  247,  329,  336,  413. 
Girdle,  322. 

Glass-rope  sponge,  102. 
Globigerina,  21. 
Globigerina  ooze,  21. 
Gloiosiphonia,  78,  94. 

G.  capillaris,  78,  94. 
Gloiosiphonieae,  78,  94. 
Glove  sponge,  104. 
Glycera,  161,  180. 

G.  americana,  161,  180.    " 

G.  dibranchiata,  161,  i8o. 
Glyceridse,  161,  179. 
Glycimeridse,  407,  459. 
Glycimeris,  407,  459. 

G.  generosa,  407,  459. 
Glyphis,  324,  358. 

G.  aspersa,  324,  358. 
Gonads,  135,  341. 
Gonangium,  118. 
Gonophore,  118. 
Goose-barnacle,  252 
Gorgonacea,  141,  152. 
Gorgonia  anceps,  Plate  XLVI, 

G.  flabellum,  Plate  XLVII. 
Gracilaria,  77,  84. 

G.  lichenoides,  39. 

G.  multipartita,  77,  84. 

G.  spinosa,  39. 
Grantia,  100,  106. 

G.  ciliata,  100,  105,  ic6. 
Grapsidae,  241,  281. 
Grass  sponge,  104. 
Grateloupia,  78,  94. 


484 


INDEX 


G.  Cutleria,  78,  94. 
Grateloupiese,  78,  94. 
Green  glands,  246. 
Griffithsia,  15,  29,  78,  91. 

G.  Bornetiana,  78,  gi. 

G.  corallina,  29. 
Grinnellia,  29,  77,  86. 

G.  Americana,  29,  77,  86. 
Gymnogongrus,  76,  82. 

G.  Norvegicus,  76,  82. 
Gymnolaemata,  188,  193. 


H 


Halcyonoida,  141,  150. 
Halcyonoids,  142. 
Halichondria,  100,  107. 

H.  panicea,  100,  107. 
Halidrys,  63,  73. 

H.  osmunda,  63,  73. 
Halimeda,  51,  58. 

H.  opuntia,  51,  59. 

H.  tridens,  51,  59. 

H.  tuna,  51,  58. 
Haliotidse,  324,  358. 
Haliotis,  9,  312,  324,  358. 

H.  cracherodii,  324,  359. 

H.  rufescens,  324,  359. 

H.  splendens,  324,  359. 
Haliseris,  63,  71. 

H.  polypodioides,  63,  71. 
Halosaccion,  78,  95. 

H.  ramentaceum,  78,  95. 
Halymenia,  78,  94. 

H.  ligulata,  78,  94. 
Haminea  solitaria,  324,  351. 
Harmothoe,  161,  174. 

H.  imbricata,  161,  174. 
Heart,  416. 

Heart  and  vascular  system,  341. 
Heart-urchins,  218,  226. 
Heliaster,  204,  205,  212. 

H.  multiradiata,  204,  212. 
Heliasteridae,  204,  212. 
Helipora,  147. 
Helmet-shells,  380, 
Helminthocladieae,  76,  79. 
Hemigrapsus,  241,  281. 

H.  nudus,  241,  281. 

H.  oregonensis,  241,  281. 
Hemimyaria,  472. 
Herbarium,  17. 
Hermit-crabs,  12,  258,  259,  264, 

362. 
Heterocoela,  100. 
Heterograpsus  nudus,  281. 

H.  oregonensis,  281. 
Heterorrhaphidse,  100. 
Hildenbrandtia,  78,  95. 

H.  rosea,  40,  78,  95. 
Himanthalia,  63,  71. 

H.  lorea,  63,  71. 
Hippa,  10,  240,  268. 

H.  analoga,  240,  269. 

H.  talpoida,  10,  11,  240,  268. 
Hippasteria,  204,  209. 

H.  phrygiana,  204,  209. 
Hippidae,  240,  268. 
Hippoconcha,  240,  264. 

H.  arcuata,  240,  264. 
Hippospongia,  100,  108. 


H.  canaliculata,  100,  108. 

H.   canaliculata,   var.   fla- 
bellum,  100,  log. 

H.  canaliculata,  var.  gos- 
sypina,  100,  108. 

H.  equina,  100,  108. 

H.  equina,  var.  agaricina, 
108. 

H.  equina,  var.  cerebrifor- 
mis,  100,  108. 

H.  equina,  var.  dura,  108. 

H.   equina,    var.    elastica, 
100,  108. 

H.   equina,  var.   meandri- 
formis,  100,  108. 
Hircinia,  100,  109. 

H.  campana,  100,  log. 
Histology,  20. 
Holdfasts,  26. 
Holocampa,  141,  145. 

H.  producta,  141,  145. 
Holothuria  edulis,  232. 
Bolothurians,  202,. 203. 
Holothuroidea,  200,  228,  229. 
Homarus,  240,  261. 

H.  americanus,  240,  262. 

H.  capensis,  261. 

H.  vulgaris,  261. 
Homorrhaphidse,  100. 
How  to  arrange  a  herbarium, 

Hyas,  241,  284,285. 

H.  araneus,  241,  285. 

H.  coarctatus,  241,  285. 

H.  lyratus,  241,  285. 
Hybocodon,  124. 

H.  prolifer,  116,  124. 
Hydractinia,  116,  122. 

H.  polyclina,  116,  122,  266. 
Hydrallmania  falcata,  127. 
Hydranth,  118,  119. 
Hydrocorallina,  117,  129. 
Hydroids,  22,  114,  119. 
Hydrorhiza,  118. 
Hydrosoma,  118. 
Hydrotheca,  118. 
Hydrozoa,  112,  114,  116,  119, 

120. 
Hypnea,  77,  84. 

H.  musciformis,  77,  84. 


Ideal  mollusk,  317. 
Idotea, 242,  293. 

I.  irrorata,  293. 

I.  marina,  242,  293. 

I.  metallica,  242,  294. 

I.  ochotensis,  242,  294. 

I.  w^osnesenskii,  242,  294. 
Idyia,  154,  157. 

I.  cyanthina,  154,  158. 

I.  roseola,  154,  157. 
Inarticulata,  188. 
Infusoria,  21,  101. 
Interambulacral     areas,     201, 

202,  218. 
Introvert,  186. 
Iridaea,  76,  82. 
Isopoda,  242,  291. 
Isopods,  12. 


Janthina,  325,  364. 

J.  fragilis,  325,  365. 
Janthinidee,  325,  364. 
Jellyfishes,  7,  44,  112,  115,  119, 

134- 
Jonah  crab,  277. 

K 

Kelp,  38. 
Kingdom,  19. 
Kitchen-middens,  432. 


Labial  palps,  416. 

Labiosa  canaliculata,  447. 

Lacuna,  309,  326,  373. 

L.  vincta,  12,  44,  326,  373. 
Lady-crab,  276. 
Lambrus,  241,  286. 

L,  pourtalesii,  241,  286. 
Lamellibranchiata,  409. 
Lamelliform,  303. 
Laminaria,  43,  63,  70. 

L.  digitata,  44,  63,  70. 

L.  longicruris,  63,  70. 

L.  saccharina,  63,  70. 
Laminariacese,  31,  35,  38,  63, 

64,  68. 
Laminarian  zone,  30,  31. 
Larva,  201. 
Larvacea,  472. 
Laurencia,  77,  89. 

L.  pinnatifida,  77,  89= 
Laver,  38. 
Leathesia,  62,  68. 

L.  difformis,  41,  68. 

L.  tuberiformis,  68. 
Leda,  309,  405,  422. 

.L.  tenuisulcata,  405,  422. 
Lepas,  239,  250,  252. 

L.  anatifera,  239,  253. 

L.  pectinata,  239,  253. 

L.  striata,  239,  253. 
Leptodora,  238. 
Leptogorgia  Agassizii,  Plate 
XLVII. 

L.  rigida,  Plate  XLVIL 
Leptoliniae,  116,  121. 
Leptomedusse,  116. 
Leptoplana,  160,  166. 

L.  folium,  160,  166. 
Lessonia,  36,  63. 
Leucosolenia,  100,  106. 

L.  botryoides,  100,  106. 
Liagora,  76. 
Libinia,  241,  284. 

L.  dubia,  241,  284. 

L.  emarginata,  241,  284. 
Ligament,  417. 
Limnoria,  242,  292. 

L.   lignorum,   13,  242,  290, 
292. 
Limpets,  9. 
Limulus,  242,  294, 

L.  moluccanus,  295. 

L.  polyphemus,  242,  294. 


INDEX 


485 


Linerges,  133,  139. 

L.  mercurius,  133,  139. 
Lines  of  growth,  344,  347. 
Lineus  marinus,  167. 

L.  sanguineus,  168. 
Lingual  ribbon,  £103,  340. 
Lip,  inner,  344. 

Outer,  344. 
Littiocysts,  135. 
Lithodes,  240,  270. 

L.  maia,  240,  270. 
Lithodidae,  240,  270. 
Littoral,  23. 

Species,  308. 

Zone,  30. 
Littorina,  9,  309,  311,  325,  338, 
370. 

L.  angulifera,  325,  372. 

L.  irrorata,  325,  372. 

L.  litorea,8,  41,  42,  325,  371. 

L.  palliata,  42,  325,  372. 

L.  planaxis,  325,  373. 

L.  rudis,  41,  42,  325,  371, 

L.  scutulata,  325,  373. 
Littorinella  minuta,  12. 
Littorinidae,  325,  338,  370. 
Livona,  325,  362. 

L,.  pica,  268,  325,  362, 
Lizzia,  120. 
Lobata,  154,  156. 
Lobsters,  240,  247,  250,  258,  259, 

261. 
Loligo,  464,  467,  469. 

L.  brevis,  464,  469. 

L.  Pealei,  464,  469. 
Lomentaria,  77,  85. 

L.  Baileyana,  77,  85. 
Lophophoi-e,  190,  193. 
Lophothuria,  228. 

L.  fabricii,  228,  232. 
Loripes,  406,  443. 

L.  edentula,  406,  443. 
Lottia,  324,  357. 

L.  gigantea,  324,  357. 
Lovenia,  217,  227. 

L.  cordiformis,  217,  227. 
Loxorhynchus,  241,  285. 

L.  crispatus,  241,  285. 
Lucapina,  324,  358. 

L.  crenulata,  324,  358. 
Lucernaria,  133,  136. 

L.  auricula,  133,  136. 
Lucina,  311,  406,  442. 

L.  californica,  406,  443. 

L.  dentata,  406,  443. 

L.  floridana,  406,  442. 

L.  nuttallii,  406,  443. 

L.  pennsylvanica,  406,  442. 

L.  tigrina,  406,  442. 
Lucinidae,  406,  442. 
Luidia,  204,  209. 

L.  alternata,  204,  209. 

L.  clathrata,  204,  209. 

L.  senegalensis,  204,  209. 
Lumbriconereis,  161,  179. 

L.  tenuis,  161,  179. 
Lunatia,  12,  309,  314,  325,  367. 

L,  heros,  10, 12,  44,  325,  367. 
■  L.  lewisii,  325,  368. 

L.  triseriata,  325,  367. 
Lunulas,  224,  303,  418. 
Lyngbya,  48. 

L.  aestuarii,  50. 


L.  ferruginea,  50. 
L.  majuscula,  50. 


M 


Macoma,  406,  444. 

M.  baltica,  406,  445. 

M.  nasuta,  406,  444. 

M.  proxima,  406,  445. 

M.  secta,  406,  444. 

M.  tenta,  406,  445. 
Macrocystis,  35,  63, 

M.  pyrifera,  36,  70. 
Macrura,  240,  258,  259,  272. 
Mactra,  310,  406,  410,  446. 

M.  lateralis,  406,  447. 

M.  ovalis,  406,  447. 

M.  similis,  406,  447. 

M.  solidissima,  406,  446. 
Mactridae,  406,  446. 
Madreporic  plate,  201, 203,  206, 

218. 
Maiidae,  241,  284. 
Malacostraca,  239,  257. 
Mandibles,  246,  258. 
Mantle,  303,  316,  319,  328,  331, 

410. 
Mantle  cavity,  303,  319,  336. 
Mantle  fusion,  412. 
Margarita,  309,  325,  360. 

M.  cinerea,  325,  360. 

M.  helicina,  12,  44,  325,  360. 

M.  undulata,  325,  360. 
Margin,  417. 

Anterior,  417. 
.  Dorsal,  417. 

Posterior,  417. 

Ventral,  417. 
Niarginella,  311,  327,  399. 

M.  apicina,  327,  399. 
Marginellidae,  327,  399. 
Marine  invertebrates,  97. 
Maxillse,  243,  246,  258. 
Maxillipeds,  243,  246,  258. 
Meckelia,  160,  169. 

M.  ingens,160,  169. 

M.  rosea,  160,  169. 
Mediaster,  204,  209. 

M.  aequalis,  204,  209. 
Megalops,  248,  273. 
Meleagrina      margaritifera, 

313,  430,  431. 
Melita  nitida,  290. 
Mellita,  217,  225. 

M.  testudinata,  217,  225. 
Melobesia,  78,  96. 
Melongena,  311,  327,  396. 

M.  corona,  327,  396. 
Membranaceous,  27. 
Membranipora,  188,  192,  196. 

M.  lineata,  188,  196. 

M.  pilosa,  43,  188,  196. 

M.  tenuis,  188,  197. 
Menippe,  241,  280. 

M.  mercenaria,  241,  280. 
Meristomes,  242,  294. 
Mesoderm,  loi,  118. 
Mesoglcea,  62,  68. 

M.  divaricata,  62,  68. 

M.  virescens,  62,  68. 


Metalia,  217,  227. 

M.  pectoralis,  217,  227. 
Metameres,  243. 
Metapodium,  376. 
Metazoa,  loi. 

Metridium  marginatum,  42. 
Microciona,  100,  107. 

M.  prolifera,  100,  107. 
Microcladia,  78,  93. 

M.  borealis,  78,  93. 

M.  Coulteri,  78,  93. 
Millepora,  129. 

M.  alcicornis,  117,  129. 
Mitra,  313. 
Mnemiopsis,  154,  157. 

M.  Leidyii,  154,  157. 
Modiola,  309,  405,  426. 

M.  modiolus,  405,  428, 

M.  nigra,  429. 

M.  plicatula,  405,  429. 

M.  recta,  405,  429. 

M.  tulipa,  405,  429. 
Moera  levis,  290. 
Moina,  238. 
Moira,  217,  226. 

M.  atropos,  217,  226. 
Molgula,  473,  475. 

M.  arenata,  473,  476. 

M.  manhattensis,  473,  475. 

M.  pellucida,  473,  476. 
MoUia,  188,  197, 

M.  hyalina,  188,  197. 
Mollusca,  300,  305,  328. 
Monoceras,  312,  326,  387. 

M.  engonatum,  326,  388. 

M.  lapilloides,  326,  388. 
Monomyarian,  303,  430. 
Monostroma,  26,  51,  55. 
Monotocardia,  300,  325,  364. 
Morphology,  20. 
Moss-animals,  191. 
Mother-of-pearl,  431. 
Moulting,  248,  259,  263. 
Mounting  seaweeds,  16. 
Mouth,  329,  333. 
Mud-crabs,  12. 
Muddy  shores,  12. 
Multivalve,  307. 
Murex,  326,  331,  382. 

M.  fulvescens,  383. 

M.  pomum,  326,  383. 

M.  rufus,  326,  382. 

M.  tenuispina,  343,  347. 
Muricea      specifera,      Plate 

XLVI. 
Muricidae,  326,  381. 
Muricinae,  326,  381,  385. 
Muscles,  248. 
Musical  sands,  2. 
Mussel,  great  horse-,  428. 
Mussels,  43,  321,  426. 
Mya,  309,  407,  456. 

M.  arenaria,  3,  42,  44,  311, 
407,  456. 
Mycedium      fragile,      Plate 

XLV. 
Myidse,  407,  456. 
Myrionema,  62,  68. 
Mysis,  239,  257. 

M.  sternolepsis,  239,  257. 
Mytilidae,  405,  426. 
Mytilus,  41,  309,  405,  426. 

M.  californicus,  405,  428. 


486 


INDEX 


M.  edulis,  42,  43,  287,  405, 

427,  428, 
M.  hamatus,  405,  428. 


N 


Naming  of  plants,  28. 
Nanomia,  130. 

N.  cara,  117,  130. 
Narcomedusae,  117. 
Nassa,  3,  10,  12,  327,  335,  390. 

N.  fossata,  327,  391. 

N.  mendica,  3'27,  391. 

N.  obsoleta,  10,  12,  327,  390. 

N.  perpinguis,  327,  391. 

N.  tegula,  327,  391. 

N.  trivittata,  10, 11,  327,  390. 

N.  vibex,  327,  391. 
Nassidae,  327,  "^90. 
Natica,  311,  325,  334,  367. 

N,  canrena,  325,  368. 

N.  clausa,  325,  368. 

N.  heros,  367. 
Naticidae,  325,  366. 
Nauplius,  248,  251. 
Nautilus,  328,  467. 
Navicula  ostrearia,  435. 
Nekton,  23. 
Nemalion,  76,  79. 

N.  multifidum,  76,  79. 
Nemalionaceae,  76,  79. 
Nemathelminthes,   1.59,    161, 

170. 
Nematoda,  161,  170. 
Nematophore,  118. 
Nemerteans,  167. 
Nemertes,  160,  169. 

N.  socialis,  IfO,  i6g. 

N.  viridis,  160,  169. 
Nemertinea,  160,  167. 
Neopanopeus,  241. 

N.  texana,  241,  281. 
Nephridia,  319. 
Nephridiura,  303. 
Nephthydidae,  161,  177. 
Nephthys,  161,  178. 

N.  ingens,  161,  178. 

N.  picta,  161,  178. 
Nereidae,  161,  176. 
Nereis,  161,  176. 

N,  limbata,  101, 177. 

N.  pelagica,  161,  177. 

N.  virens,  161,  177. 
Nereocystis,  63,  70. 

N.  Liitkeana,  35. 
Nerine,  161,  181. 

N.  agilis,  161,  i8t. 

N,  coniocephala,  161,  181. 
Nerita,  325,  363. 

N.  peleronta,  325,  363. 

N.  tessellata,  325,  363. 

N.  versicolor,  325. 
Neritidae,  325,  363. 
Neritina,  311,  325,  363. 

N.  reclivata,  325,  364. 

N.  viridis,  325,  364. 
Nervous  system,  247,  320. 
Neverita,  309,  325,  368. 

N.    duplicata,  11,  325,  367. 

N.  recluziana,  325,  368. 
Nicothoe,  239,  250. 


Nidorella,  204,  210. 

N.  armata,  204,  210. 
Nitophyllum,  77,  85. 

N.  laceratum,  77,  85. 

N.  punctatum,  77,  86, 

N.  Ruprechteanum,  77,  86. 
Noah's-ark  shell,  426. 
Node,  303. 
Nodules,  344. 

Non-Calcarea,  100,  104,  106. 
Norrisia,  312. 
Nostocaceae,  48. 
Nucula,  309,  405,  422. 

N.  proxima,  405,  422. 
Nuculidae,  405,  421. 
Niidibrancli,  328,  349,  353. 
Nudibranchiata,  303,  324,  352. 
Nullipores,  31,  147. 
Nummulites,  22. 

o 

Obelia,  125. 

O.  commissuralis,  116,  125. 
Oceania,  125. 

O.  languida,  116,  125. 
Ocinebra,  326,  384. 

O.  circumtexta,  385. 

O.  interfossa,  326,  385. 

O.  lurida,  326,  384. 

O.  poulsoni,  326,  384. 
Octopi,  315. 

Octopoda,  301,  464,  468. 
Octopus,  464,  468. 
Oculina,  141,  148. 
Ocypoda,  11,  241,.  282. 

O.  arenaria,  241,  274,  282. 
Ocypodidae,  241,  282. 
Odontophore,  303. 
Oliva,  10,  311,  313,  327,  334,  400. 

O.  literata,  327,  400. 
Olivella,  10,  312,  327,  400. 

O.  biplicata,  327,  400. 

O.  boetica,  327,  401. 

O.  mutica,  327,  400. 
Olividae,  327,  400. 
Ommastrephes,  464,  468,  469. 

O.  illecebrosus,  464,  469. 
Opercula,  193. 

Operculum,  254,  303,  331,  355. 
Ophiocoma,  213,  216. 

O.  aethiops,  213,  216. 

O.  Alexandri,  213,  216. 

O.  riisei,  213,  216. 
Ophiopholis,  213,  215. 

O.  aculeata,  43,  213,  215. 
Ophiothrix,  213,  216. 

O.  angulata,  213,  216. 
Ophiurida,  213,  215. 
Ophiuroidea,  200,  213,  214. 
Opisthobranchiata,  300,  324, 

349,  350. 
Oral,  202. 

Surface,  201. 
Oibits,  243. 
Orchestia,  11,  43,  242,  289, 

O.  agilis,  242,  289. 
Organ-pipe  coral,  151. 
Organs  of  feelins,  249. 
Orifice,  190,  412. 
Oscillaria,  48,  49. 
Osphradiuni,  303,  339. 


Ossicles,  201,  203,  218. 
Ostracoda,  238. 
Ostrea,  405,  410,  435. 

O.  edulis,  435. 

O.  frons,  405,  435. 

O.  lurida,  405,  435. 

O.  virginica,  310,  405,  435. 
Ostreidae,  405,  432. 
Otocysts,  165,  303. 
Otter  Cliffs,  43. 
Ovalipes,  241,  276, 

O.  ocellatus,  241,  276. 
Ovicell,  190,  193. 
Oystei'-crab,  287. 
Oyster-culture,  432. 
Oysters,  321,  432. 

Pearl-,  430,  431,  432. 


Pacific  faunal  divisions. 
Pacygrapsus,  241,  282. 

P.  crassipes, 241,  282. 
Padina,  63,  71. 

P.  pavonia,  63,  71. 
Paguridae,  240,  264. 
Pagurus,  240,  267. 

P.  bernhardus,  240,  267. 

P.  longicarpus,  240,  267. 

P.  poUicaris,  240,  267. 
Palaemonetes,  240,  260. 

P.  vulgaris,  240.  260. 
Palaemon  vulgaris,  260. 
Pallial  line,  £03,  418. 

Sinus,  303,  419. 
Palps,  176,  416. 
Palpus,  258. 
Panamic  province,  312, 
Pandora,  407,  463. 

P.  trilineata,  407,  463. 
Pandoridae,  407,  463. 
Panopeus,  12,  281. 
Pantopoda,  242,  296. 
Panulirus,  240,  263. 

P.  americanus,  263. 

P.  argus,  240,  263. 

P.  interruptus,  240,  263. 
Papillaceous,  303. 
Parapliyses,  72. 
Parapodia,  171. 
Parenchyma,  26. 
Parypha,  123. 

P.  crocea,  116,  123. 
Peachia,  144. 
Pearls,  430,  431. 
Pecten,  S09,  405,  435. 

P.  aequisulcatus,  405,  438. 

P.  dislocatus,  405,  437. 

P.  hastatus,  405,  438. 

P.  irradians,  405   437. 

P.  islandicus,  405,  436. 

P.  jacobius,  436. 

P.  magellanicus,  287,  405, 
436. 

P.  tenuiscostatus,  436. 
Pectinidae,  405,  435. 
Pedal  opening,  412. 
Pedata,  228,  231. 
Pedicellariae,  201,  205,  219. 
Pedicellina,  189,  198. 

P.  americana,  189,  198. 


INDEX 


487 


Pelagia,  133,  139. 

P.  cyanella,  133,  139. 
Pelanic.  23. 

Flora,  38. 
Pelecypoda,  301,  320,  321,  405, 
409,  420. 

Classification  of,  419. 
Peltogaster,  239,  256. 
Pen,  467. 
Penaeus,  240,  260. 

P.  brasiliensis,  240,  260. 

P.  setiferus,  240,  26O. 
Penicillus,  51,  58. 

P.  capitatus,  51,  58. 

P.  dumentosus,  51,  58. 

P.  Phoenix,  51,  58, 
Pennaria,  124. 

P.  gibbosa,  116,  124. 

P.  tiarella,  116,  124. 
Pennatula,  141. 

P.  aculeata,  Plate  XLVII. 

P.  borealis,  Plate  XLVII. 
Pennatulacea,  141,  153. 
Pentaceros,  204,  210. 

P.  occidentalis,  204,  210. 

P.  reticularis,  204,  210. 
Pentacerotidae,  204,  210. 
Pentacrinus,  234,  235. 
Pentacta,  228,  232. 

P.  frondosa,  43,  228,  232. 
Pentagonasteridse,  204,  209, 
Pericardium,  341,  416. 
Pericolpa,  133,  136. 

P.  quadrigata,  133,  136. 
Peridiniese,  38. 
Periostracum^  303,  425. 
Perisaltic,  172. 
Perisarc,  118,  119. 
Peristome,  190, 194,  218,  303. 
Peristoniium,  176. 
Periwinkles,  371. 
Perna,  405,  432. 

P.  ephippium,  405,  432. 
Peromedusae,  133,  136. 
Petricola,  407,  452. 

P.  carditoides,  407,  452. 

P.  pholadiformis,  407,  452. 
Petricolidae,  407,  452. 
Petrocelis,  78,  95. 

P.  cruenta,  40,  78,  95. 
Petrolisthes,  240,  270. 

P.  armatus,  240,  270. 

P.  sexspinosus,  240,  270. 
Peyssonnelia,  78,  95. 

P.  Dubyi,  78,  95. 
Phseophyceae,  28,  61,  62, 
Phanerogams,  25. 
Phanerozonia,  204,  208, 
Phascolosoma,  162,  186. 

P.  Gouldii,  162,  186. 
Pholadidae,  407,  460. 
Pholas,  407,  460. 

P.  californica,  407,  461. 

P.  costata,  407,  461. 

P.  truncata,  407,  461. 
Phoxichilidium,  242,  297. 

P.  maxillare,  242,  297. 
Phyla,  ig. 
Phyllitis,  62,  66. 

P.  fascia,  62,  66. 
Phyllodoce,  161,  175. 

P.  gracilis,  161,  175. 
Phyllodocidae,  161,  175. 


Phyllolithodes,  240,  271. 

P.  papillosus,  240,  271. 
Phyllonotus  pomum,  382. 
Phyllophora,  76,  81. 

P.  Brodiaei,  76,  82. 

P.  membranifolia,  76,  82. 
Phyllopoda,  238. 
Phyllospora,  63,  73. 

P.  Menziesii,  63,  73. 
Phylum,  19. 
Phyncopodia  helianthoides, 

207. 
Physalia,  131. 

P.  arethusa,  117,  131. 
Pikea,  78,  94. 

P.  californica,  78,  94. 
Pill-bugs,  291. 
Pinna,  405,  431. 

P.  muricata,  405,  431. 

P.  seminuda,  405,  431. 
Pinnotheres,  241,  287. 

P.  maculatum,  287. 

P.  ostreum,  241,  287. 
Pinnotheriidae,  241,  287. 
Pitho,  241,  286. 

P.  aculeata,  241,  286. 
Placunanomia,  405,  425. 

P.  macrochisma,  405,  425. 
Planaria,  160,  167. 

P.  grisea,  160,  167. 
Planarians,  166. 
Planarian  worms,  12. 
Plankton,  21,  23. 
Planocera,  160,  166. 

P.  nebulosa,  160,  166. 
Planula,  120,  135. 
Platyhelminthes,     159,     160, 

164, 
Platyonichus  ocellatus,  276. 
Pleurobrachia,  154,  156. 

P.  rhododactyla,  154,  156. 
Pleurococcus,  26. 

P.  vulgaris,  25. 
Plocamium,  77,  85. 

P.  coccineum,  77,  85. 
Plumularia,  127. 

P.  falcata,  116,  127. 
Plumularians,  116,  127. 
Pluteus,  201,  220. 
Polian  vessels,  201. 
Polina,  160,  170. 

P.  glutinosa,  160,  170. 
Polychaeta,  161,  172. 
Polycirrus,  161,  182. 

P.  eximius,  161,  182. 
Polycladida,  160,  165. 
Polyides,  78,  95, 

P.  rotundus,  78,  95. 
Polymastia,  100,  106. 

P.  robusta,  100,  106. 
Polynices,   12,   310,   314,  325, 
335,  367. 

P.  duplicata,   11,   325,   344, 
367- 

P.  heros,  3,  10,  44,  325,  343, 
367. 

P.  lewisii,  325,  368. 

P.  recluziana,  325,  368. 

P.  triseriata,  325,  367. 
Polynoe,  161,  174. 

P.  squamata,  161,  174. 

P.  sublevis,  161,  174. 
Polyphemus,  238. 


Polypide,  190,  192. 
Polyplacophora,  300,  321. 
Polyps,  111,  114,  119. 
Polysiphonia,  77,  87. 

P.  Baileyi,  77,  88. 

P.  dendroidea,  77,  87. 

P.  fastigiata,  43,  77,  87. 

P.  fibrillosa,  77,  88. 

P.  Harveyi,  77,  88. 

P.  nigrescens,  77,  87. 

P.  Olneyi,  77,  88. 

P.  parasitica,  77,  87. 

P.  urceolata,  77,  88. 

P.  urceolata,  var.  formosa, 
77,  88. 

P.  variegata,  77,  88. 

P.  violacea,  44,  77,  88. 

P.  W^oodii,  77,  89. 
Polyzoa,  8, 188,  191. 
Polyzoans,  8,  12,  22. 
Pontonema,  161,  170. 

P,  marinum,  161,  170. 
Porcelanor.s,  304,  345. 
Porcellana,  240,  269. 

P.  sayana,  240,  269. 
Porcellanasteridae,  204,  208. 
Porcellanidae,  240,  269. 
Porcupine  Island,  42. 
Porifera,  100,  loi. 
Porites,  147. 

P.  astraeaoides,  Plate  XLV, 

P.  furcata,  Plate  XLV. 
Porocidaris,  217,  222. 

P.  sharreri,  217,  222. 
Porphyra,  43,  78,  96. 

P.  laciniata,  78,  96. 

P.  vulgaris,  38,  78,  96. 
Porpita,  132. 
Portunidae,  241,  274. 
Prawns,  258,  259. 
Preserving  invertebrates,  14. 
Prionitis,  78,  94. 

P.  Andersonii,  78,  94. 

P.  lanceolata,  78,  94. 
Proboscis,  333. 
Procerodes,  160,  167. 

P.  frequens,  160,  167. 
Propodium,  335. 
Prosobranchiata,    300,      324, 

349,  355. 
Prostomium,  176,  243. 
Protista,  22. 
Prdtobranchiata,     301,     405, 

420,  421. 
Protococcaceae,  38. 
Protococcus  nivalis,  25,  33. 
Protophyta,  21. 
Protozoa,  21,  101. 
Pseudolamellibranchiata, 

301,  405,  420,  429. 
Psilaster,  204,  209, 

P.  florae,  204,  209. 
Psolus  ephippiger,  231. 

P.  fabricii,  232. 
Pterogorgia    acerosa,    Plate 

XL  VI. 
Pteronotus,  326,  384. 

P.  festivus,  326,  384. 
Ptilota,  78,  92. 

P.  densa,  78,  92. 

P.  elegans,  78,  92. 

P.  hypnoides,  78,  92. 

P.  serrata,  78,  92. 


488 


INDEX 


Pugettia,  241,  285. 

P.  gracilis,  241,  285. 
Pulmonata,  300,  331,  338,  349. 
Punctaria,  02,  65. 

P.  latifolia,  62,  65. 

P.  plantaginea,  62,  66. 

P.  tenuissima,  62,  66. 
Purpura,   8,   9,  309.  312,  326, 
386,  387. 

P.  crispata,  326,  387. 

P.  haemastoma,  326,  387, 

P.  lapillus,  41,  42,  314,  326, 
386. 

P.  lima,  326,  387. 

P.  patula,  326,  386. 

P.  saxicola,  326,  387. 
Purpurinae,  326,  385. 
Pycnogonida,  242,  296. 
Pycnogonidse,  9. 
Pylopagurus,  268. 
Pyloric  cfeca,  208. 
Pyrocystis  noctiluca,  33. 
Pyrosoma,  472. 
Pyrosomata,  472. 
Pyrula,  10,  326,  379. 

P.  papyratia,  326,  379. 


Radiata,  113. 
Radiates,  20. 
Radula,  304,  317,  340. 
Reeta,  406,  447. 

R.  canaliculata,  406,  447. 
Ralfsia,  62,  65. 
Ralfsiacese,  62,  65. 
Rataria,  132. 
Receptacles,  72. 
Red  crab,  278. 
Red  seaweeds,  76,  79. 
Red  snow,  33. 
Reef-builders,  147. 
Reef-corals,  142,  146. 
Regularia,  217. 
Reticulated,  304. 
Rhabdocoelida,  160,  167. 
Rhabdonia,  77,  83. 

R.  Coulteri,  77,  84. 

R.  tenera,  77,  83. 
Rhithropanopeus,  241. 

R.  harrisii,241,28i. 
Rhizocephala,  239,  256. 
Rhizophyllidese,  78,  95. 
Rhizostomae,  133,  139. 
Rhodactinia,  141,  145. 

R.  davidsii,  141,  145. 
Rhodomela,  77,  89. 

R.  floccosa,  77,  90. 

R.  larix,  77,  90. 

R.  Rochei,  77.  89. 

R.  subfusca,  77,  89. 
Rhodomeleae,  77,   86. 
Rhodophyceae,  28,  76,  79. 
Rhodophyllidese,  77,  83. 
Rhodophyllis,  77,  83. 

R.  veprecula,  77,  83. 
Rhodospermese,  79. 
Rhodymenia,  77,  85. 

R.  palmata,  38, 42,  43,  77,  85. 
Rhodymeniaceae,  77,  84. 
Rhodymenieae,  77,  85. 
Ring-canal,  201,  203. 


Rock-crab,  277,  280. 
Rockweeds,  8. 
Rocky  shores,  7. 
Rodicks  Weir,  44. 
Root-mouth  jellyfishes,  139. 
Rostrum,  243. 
Roundworms,  170. 


Sabella,  162,  184. 

S.  microphthalma,162,  184. 
Sabellidae,  162,  184. 
Sacculina,  239,  256. 
Sagartia,  141,  145. 

S.  leucolena,  141,  145. 
Salpa,  472,  474,  475. 
Sand-crab,  282. 
Sand-dollar,  11,  44,  225. 
Sandpiper,  5. 
Sandy  shores,  10. 
Sapphirina,  239,  250. 
Sargaiiso  Sea,  33. 
Sargassum,  26,  63,  64,  73. 

S.  bacciferum,  34,35,63,  74. 

S.  Montagnei,  63,  74. 

S.  vulgare,  63,  74. 
Sarsia,  116,  123. 

S.  mirabilis,  123. 
Saxicava,  41. 
Saxidomus,  406,  452. 

S.  nuttallii,  406,  452. 
Scala,  325,  365. 

S.  angulata,  325,  366. 

S.  groenlandica,  325,  366. 

S.  lineata,  325,  366. 

S.  multistriata,  325,  366. 
Scalidae,  325,  365. 
Scallops,  12. 

Scaphopoda,  320,  321,  327, 402. 
Schizaster,  217,  227. 

S.  fragilis,  217,  227. 
Schizopoda,  239,  257, 
Scinaia,  76,  80. 

S.  furcellata,  76,  8c. 
Scrobicularia,  413. 
Sculpture,  304. 
Scurria,  312. 
Scuta,  254. 
Scutellidae,  217,  225. 
Scyllarus,  258,  263. 
Scyphozoa,  112,  115,  133,  134. 
Sea-acorns,  254. 
Sea-anemones,  112,  142. 
Sea-blubbers,  134. 
Sea-colanders,  42,  69. 
Sea-cucumbers,   43,    200,    202, 

229. 
Sea- eggs,  221. 

Sea-fans,  114,  115, 142,  147,  152. 
Sea-feathers,  152. 
Sea-hares,  351. 
Sea-lilies,  200,  234. 
Sea-mats,  192. 
Sea-otters'  cabbage,  35. 
Sea-peach,  476. 
Sea-pens,  142,  153. 
Sea-slugs,  349. 
Sea-spiders,  9,  296. 
Sea-squirts,  474. 
Sea-urchins,  43,  114,  200,  203, 
218,  220. 


Sea-whips,  142,  152. 
Sedentaria,  161,  180. 
Segment,  243. 
Segmented  worms,  170. 
Semostomae,  133,  137. 
Sense-organs,  135. 
Sepia,  464,  467,  468. 
Septibranchiata,  420. 
Serpula,  162,  185. 

S.  dianthus,  162,  185. 
Serpulidse,  162,  184.  . 
Sertularia,  126. 

S.  argentea,  43,  116,  127. 

S.  cupressina,  116,  127. 

S.  pumila,  43,  116,  126. 
Sertularians,   8,  116,  120,   121, 

126. 
Sessile,  121,  126. 
Sheep-crab,  285, 
Sheepswool  sponge,  104,  108. 
Shell- 
Butterfly-,  323. 

Coffee-,  379. 

Conch-,  377. 

Cowry-,  377. 

Gasteropod,  342. 

Growth  of  gasteropod,  346. 

Mounds,  432. 

ISToah's-ark,  426. 

Peach-,  454. 

Pelecypod,  416,  417. 

Razor-,  457. 

Setting-sun,  444. 
Shipworm,  462. 
Shrimps,  240,  245,  258,  259. 
Sigaretus,  311,  325,  334,  369. 

S.  perspectivus,  325,  369. 
Signs  on  tlie  beach,  i. 
Singing  Beach,  2. 
Sinistral,  304,  345. 
Sinuate,  304. 
Sipho,  309,  318,  327,  393. 

S.  islandicus,  393. 

S.  pygmaeus,  327,  394. 

S.  Stimpsoni,  327,  393. 
Siphon,  304,  330,  334,  411. 

Anal,  412. 

Branchial,  412. 

Excurreut,  412. 

Functional,  411. 

Incurrent,  412. 
Siphonalia,  327,  394. 

S.  kellettii,  327,  394. 
Siphoneae,  51,  56. 
Siphonoglyphs,  143. 
Siphonophora,  117,  120,   121, 

130. 
Slphonozooids,  150. 
Siphuncle,  468. 
Sipunculoidea,  162,  185. 
Sipunculus,  162,  185. 

S.  nudus,  162,  185. 
Skates,  12,  44. 
Solaster,  204,  205,  211. 

S.  decemradiata,  204,  211. 

S.  endeca,  204,  211. 
Solasteridae,  204,  211. 
Solen,  407,  458. 

S.  ensis,  3,  458. 

S.  rosaceus,  407,  458. 

S.  sicarius,  407,  458. 
S.  viridis,  407,  458. 
Solenidae,  407,  457. 


INDEX 


489 


Solenogastres,  321. 
Solenomya,  405,  423. 

S.  borealis,  405,  423. 

S.  velum,  405,  423. 
Solenomyidse,  405,  423. 
Somite,  243. 
Sow-bugs,  291. 
Spatangoidae,  217,  226. 
Spatangoidea,  217,  226. 
Species,  20. 
Specific  name,  28. 
Sphacelaria,  62,  65. 

S.  cirrhosa,  62,  65. 

S.  radicans,  62,  65. 
Sphacelariaceae,   62,  65. 
Sphaeoplea  annulina,  37. 
Sphseridia,  219. 
Sphaerococceae,  77,  84. 
Sphaeroma,  242,  293. 

S.  destructor,  293. 

S.    quadridentaturr,     24?, 

293. 
Spicules,  102. 
Spider-crabs,  241,  284. 
Spines,  201,  205,  221. 
Spionidae,  161,  181. 
Spire,  304. 
Spirorbis,  8,  12,  162,  185. 

S.  borealis,  162,  185. 
Spirula,  464,  467,  468. 
Spirulina,  48,  49. 
Sponges,  100,  loi. 
Spongia,  104. 

S.  graminea,  109. 
Spongidae,  100. 
Spongillidae,  104. 
Spongin,  102, 
Spring-tides,  13,  15. 
Spyridia,  78,  92. 

S.  filamentosa,  78,  92, 
Squamarieae,  78,  95. 
Squame,  243. 
Squids,  464. 
Squilla,  241,  288. 

S.  empusa,  241,  288. 
Starfishes,  43, 114,  200,  203,  204, 

205,  434. 
Station  and  habits  of  the  Mol- 

lusca,  313. 
Stauromedusae,  133,  136. 
Stelosponginae,  100. 
Sternogramme,  76,  82. 

S.  interrupta,  76,  82. 
Sternorhynchus,  241,  286. 

S.  Sagittarius,  241,  286. 
Stomatopoda,  241,  288. 
Stone-canal,  201,  203. 
Stone-crab,  280. 
Stony  corals,  112,  115,  146. 
Striae,  344. 
Strobila,  135, 138. 
Strombidse,  326,  375. 
Strombus,  10,  311,  326,  376. 

S.  alatus,  376. 

S.  gigas,  826,  376,  431. 

S.  pugilis,  326,  376. 
Strongylocentrotus,  217,  223. 

S.    drobachiensis,    41,    43, 
217,  223. 

S.  franciscanus,  217,  223. 

S.     purpuratus,     217,    221, 
223. 
Structure  of  mollusks,  315. 


Stylochopsis,  160,  166. 

S.  littoralis,  160,  166. 
Suberites,  100,  106. 

S.  compacta,  100,  106. 
Suberitidae,  100. 
Suborders,  29. 
Subumbrella,  120. 
Suckers,  201,  203. 
Sun-jellies,  134,  138. 
Suture,  304,  344. 
Swimming-bell,  120. 
Swimming  crabs,  241. 
Syconidae,  100. 
Syllidae,  161,  173. 
Symmetry,  328. 
Synapta",  228,  229,  233. 

S.  roseola,  228,  233. 

S.  rotifera,  228,  233. 

S.  tenuis,  228,  233. 

S.  viviparia,  231. 

T 

Table :  Classification  of  algse— 
Elue-green,  48. 
Brown,  62. 
Grass-green,  51. 
Eed,  76. 
Classification  of — 
Actinozoa,  141. 
Arthropoda,  238. 
Asteroidea,  204. 
Cephalopoda,  464. 
Chordata,  472. 
Ctenophora,  154. 
Echinoidea,  217. 
Holothuroidea,  228. 
Hydrozoa,  116. 
Mollusca,  300. 
Molluscoida,  188. 
Ophiuroidea,  213. 
Pelecypoda,  409. 
Porifera,  100. 
Scyphozoa,  133. 
Tagelus,  310,  407,  459. 
T.  gibbus,  407,  459- 
Talitrus  longicornis,  289. 
Talorchestia,  242,  289. 
T.  longicornis,  242,  289. 
T.  megalophthalma,  290. 
Taonia,  63,  71. 

T.  atomaria,  63,  71. 
Tapes,  406,  451. 
T.  laciniata,  406,  451. 
T.  staminea,  406,  451. 
Tealia  crassiformis,  145. 
Tectarius,  311,  326,  373. 
T.  muricatus,  326. 
T.  nodulosus,  326,  373. 
Tectibranchiata,  300,  324,  350. 
Tedania,  100,  107. 
Teeth,  304,  417,  418. 
Cardinal,  418. 
Lateral,  418. 
Tellina,  311,  406,  443. 
T.  alternata,  406,  444. 
T.  bodegensis,  406,  444. 
T.  radiata,  406,  443,  444. 
T.  tenera,  406,  444. 
Tellinidae,  406,  443. 
Telson,  243,  247. 
Tentaculocysts,  135. 


Terebellidae,  161,  182. 
Teredinidae,  407,  462. 
Teredo,  407,  462. 

T.  navalis,  13,  407,  462. 
Terga,  254. 

Terms  used  in  describing  Crus- 
tacea, 243. 
Ecliinoderms,  201. 
Hydroids,  118. 
Mollusks,  302. 
Polyzoa,  190. 
Testaceous,  304. 
Tetrabranchiata,     SOI,     464, 

467. 
Tetrastemma,  160,  169. 

T.  arenicola,  160,  169. 
Thalassiophyllum,  36,68,  70. 
Thaliacea,  472. 
Thallophytes,  25. 
Thallus,  26. 
Thelepsus,  161,  182. 

T.  cincinnatus,  161,  182. 
Thorax,  243,  246. 
Thracia,  309. 
Thyone,  228,  231. 

T.  briareus,  228,  231. 
Tima,  128. 

T.  formosa,  116,  128. 
Tivela,  406,  410,  450. 

T.  crassatelloides,  406,  450. 
Toad-crab,  285. 
Toxopneustes,  217,  224. 

T.  variegatus,  217,  224. 
Trachylinae,  117,  120,  128. 
Trachymedusae,  117,  128. 
Trachynema,  128. 

T,  digitale,  117,  128. 
Transatlantic  province,  309. 
Trematoda,  160. 
Trichodesmium,  33. 
Trichotropis,  309. 
Tricladida,  160,  166. 
Triclads,  166. 
Tridacna  gigas,  313,  419. 
Triforis,  374. 
Tritonidea,  327,  394. 

T.  tincta,  327,  394- 
Trivia,  326,  378. 

T.  californica,  326,  379. 

T.  pediculus,  326,  378. 

T.  quadripunctata,  326,379. 

T.  solandri,  326,  379. 

T.  spadacea,  379. 
Trochidae,  325,  359. 
Trochiscus,  325,  362. 

T.  norrisi,  325,  362. 
Trophon,  309,  326,  383. 

T.  clathratus,  326,  383. 
Tube-feet,  203. 
Tubicola,  161,  172. 
Tuliicolous  worms,  180. 
Tubipora,  141,  147,  151. 
Tubularia,  116. 

T.  Couthouyi,  116,  123. 

T.  indivisa,  116. 
Tubularians,  116,  121,  122. 
Tubulipora,  188,  194. 

T.  flabellaris,  188,  194. 
Tunicata,  472,  474. 
Tunicates,  474. 
Turbellaria,  160,  165. 
Turbinate,  304. 
Turbinellidae,  327,  394. 


490 


INDEX 


Turbinidae,  325,  362. 
Turbo,  325,  363. 

T.  castaneus,  325,  363. 

T.  castaneus,    var.  crenu- 
latus,  325,  363. 
Tyriaii  purple,  386. 


u 

Uca,  241,  282. 

U.  minax,  241,  282. 

U.  pugilator,  241,  282. 

U.  pugnax,  241,  282. 
Udotea,  51,  58. 

U.  conglutinata,  51,  58. 

U.  flabellata,  51,  58. 
Udoteaceae,  51,  58. 
Ulothrix,  51,  53. 
Ulva,  26,  28,  29,  51,  55. 

U.  lactuca,  51,  55. 

U.  latissima,  51,  55. 

U.  Linza,  56. 

U.  rigida,  55, 
Ulvaceae,  28,  51,  52,  53,  54. 
Umbilicus,  304,  344. 
Umbo,  304,  417. 
Uncini,  180. 

Univalves,  306,  307,  314. 
Urochorda,  472,  474. 
Urosalpinx,  11,  326,  383,  434. 

U.  cinerea,  314,  326,  383. 
Uses  of  algse,  37. 


V 

Valoniacese,  51,  56. 
Valve,  409,  416. 
Varices,  304,  344,  347. 
Vegetative  reproduction,  27. 


Vellela,  131. 

V.  limbosa,  117,  131. 
Velum,  134. 
Velutina,  309. 
Velvet  sponge,  104. 
Veneridae,  406,  447. 
Venous  sinuses,  247. 
Ventral  surface,  201. 
Ventricosa,  304. 
Venus,  406,  410,  448. 

V.  cancellata,  406,  449. 

V.  mercenaria,  406,  448. 

V.  mercenaria,   var.  mor- 
toni,  406,  449. 
Venus's  flower-baslcet,  102. 

Girdle,  157. 
Vermes,  163. 
Vermetidse,  326,  375. 
Vermicularia,  326,  375. 

V.  spirata,  326,  375. 
Vertebrates,  19. 
Vesicularia,  189,  198. 

V.  custata,  189,  198. 

V.  dichotoma,  189,  198. 
Vibracula,  190,  193. 
Visceral  mass,  415. 
Voluta,  313,  327,  398. 

V.  junonia,  327,  398,  399. 
Volutidae,  327,  398. 
A^ulgar  names,  29. 


w 

Walking  crabs,  241. 
Water-vascular     system,    201, 

202,  206,  231. 
West  Indian  division,  24. 
Wharves  and  bridges,  13. 
Whelks,  44. 
Whorl,  304,  343. 
Whorls,  nepionic,  344. 


Worms,  159,  163. 
Bristle-,  171. 
Cheetopod,  172. 
Clam-,  176. 
Flat-,  164. 

Nemertean,  167,  169. 
Polychsete,  172. 
Polyclad,  165, 
Eound-,  170. 
Segmented,  170. 
Tubicolous.  180. 


Xiphosura,  242,  294. 
Xylotrya,  462. 


Yellow  sponge,  104. 
Yoldia,  309,  405,  422. 

Y.  limatula,  405,  422. 

Y.  sapotilla,  405,  423. 

Y.  thraciaeformis,  405,  422. 


Zirphaea,  407,  461. 

Z.  crispata,  407,  461. 
Zoantharia,  141,  142. 
Zoarium,  190,  192. 
Zoea,  248,  263,  273. 
Zooecium,  190,  192. 
Zonaria,  63,  70. 

Z.  lobata,  63,  70. 
Zobids,  118,  119. 
Zoophytes,  113,  119. 
Zostera  marina,  12. 
Zygodactyla,  128. 

Z.  groenlandica,  116,  128. 


COERIGENDA 

Page      6.  Second  line  from  tlie  bottom,  for  ''  they  "  read :  Anemones. 

41.  Line  20,  for  '^  moenas  "  read  :  mcenas. 

43.  Last  line,  for  "■  they  "  read :  animals. 

44.  Line  27,  for  ^' Ci/«ma"  read:   Cyanea. 
102.  Last  line,  for  ^'flagellcEte''^  read:  flagellate. 
196.  Line  27,  for  "■  species  "  read :  specimens. 
224.  Line  16,  for  "  lunales  "  read :  lunules. 

Plate  Lxxxiv,  6.     For  ''  Glvdmeris''''  read:  Glycimeris. 


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